{"id":35801,"date":"2019-10-31T22:06:24","date_gmt":"2019-10-31T19:06:24","guid":{"rendered":"https:\/\/prohoster.info\/blog\/kak-vybrat-shd-ne-vystreliv-sebe-v-nogu\/"},"modified":"2019-10-31T22:06:24","modified_gmt":"2019-10-31T19:06:24","slug":"kak-vybrat-shd-ne-vystreliv-sebe-v-nogu","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/administrirovanie\/kak-vybrat-shd-ne-vystreliv-sebe-v-nogu","title":{"rendered":"Jak vybrat SOD, ani\u017e bych si vyst\u0159elil do nohy","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<h2>\u00davod<\/h2>\n<p>\nP\u0159i\u0161el \u010das koupit \u00falo\u017ei\u0161t\u011b. Kter\u00e9 vybrat, koho poslouchat? Dodavatel A vysv\u011btluje dodavatele B, a tak\u00e9 je tu integr\u00e1tor C, kter\u00fd \u0159\u00edk\u00e1 opak a doporu\u010duje dodavatele D. V takov\u00e9 situaci se i zku\u0161en\u00e9mu architektu syst\u00e9m\u016f ukl\u00e1d\u00e1n\u00ed m\u016f\u017ee zamotat hlava, obzvl\u00e1\u0161\u0165 s v\u0161emi nov\u00fdmi dodavateli a dnes popul\u00e1rn\u00edmi SDS a hyperkonvergenc\u00ed.<\/p>\n<p>Jak se v tom v\u0161em vyznat a nez\u016fstat hloup\u00fd? My (<noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/users\/antonvirtual\/\" class=\"user_link\">AntonVirtual<\/a><\/noindex> Anton \u017dbankov a <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/users\/korp\/\" class=\"user_link\">korp<\/a><\/noindex> Evgenij Elizarov) se to pokus\u00edme vysv\u011btlit jasn\u011b a srozumiteln\u011b.<br \/>\n\u010cl\u00e1nek se do zna\u010dn\u00e9 m\u00edry p\u0159ekr\u00fdv\u00e1 a v podstat\u011b je roz\u0161\u00ed\u0159en\u00edm \u201c<noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/321178\/\">Designu virtualizovan\u00e9ho datov\u00e9ho centra<\/a><\/noindex>\u201d v oblasti v\u00fdb\u011bru syst\u00e9m\u016f ukl\u00e1d\u00e1n\u00ed dat a p\u0159ehledu technologi\u00ed syst\u00e9m\u016f ukl\u00e1d\u00e1n\u00ed. Kr\u00e1tce probereme obecnou teorii, ale doporu\u010dujeme se tak\u00e9 sezn\u00e1mit s uveden\u00fdm \u010dl\u00e1nkem.<\/p>\n<h2>Pro\u010d<\/h2>\n<p>\n\u010casto lze pozorovat situaci, kdy nov\u00fd \u010dlov\u011bk na f\u00f3ru nebo ve specializovan\u00e9m chatu, jako je t\u0159eba Storage Discussions, polo\u017e\u00ed ot\u00e1zku: \u201cnab\u00edzej\u00ed mi dv\u011b varianty \u00falo\u017ei\u0161t\u011b \u2014 ABC SuperStorage S600 a XYZ HyperOcean 666v4, co doporu\u010d\u00edte?\u201d<\/p>\n<p>A za\u010dne se m\u011b\u0159it, kdo m\u00e1 jak\u00e9 zvl\u00e1\u0161tn\u00ed vlastnosti realizace stra\u0161ideln\u00fdch a nepochopiteln\u00fdch funkc\u00ed, kter\u00e9 pro nep\u0159ipraven\u00e9ho \u010dlov\u011bka zcela vypadaj\u00ed jako \u010d\u00ednsk\u00e9 p\u00edsmo. <br \/>\n<noindex><a rel=\"nofollow\" name=\"habracut\"><\/a><\/noindex><br \/>\nTak\u017ee kl\u00ed\u010dov\u00e1 a prvn\u00ed ot\u00e1zka, kterou si mus\u00edte polo\u017eit dlouho p\u0159ed porovn\u00e1v\u00e1n\u00edm specifikac\u00ed v komer\u010dn\u00edch nab\u00eddk\u00e1ch \u2014 PRO\u010c? Pro\u010d je toto \u00falo\u017ei\u0161t\u011b pot\u0159eba?<\/p>\n<p><img decoding=\"async\" alt=\"Jak vybrat SOD, ani\u017e bych si vyst\u0159elil do nohy\" src=\"\/wp-content\/uploads\/2019\/06\/4e02a50a2420483c6c4939bf264dea2a.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nOdpov\u011b\u010f bude p\u0159ekvapiv\u00e1 a velmi ve stylu Tonyho Robbins \u2014 abychom ukl\u00e1dali data. D\u00edky, kapit\u00e1ne! A p\u0159esto n\u011bkdy tak hluboce zab\u0159ed\u00e1me do porovn\u00e1v\u00e1n\u00ed detail\u016f, \u017ee zapom\u00edn\u00e1me, pro\u010d to v\u0161echno vlastn\u011b d\u011bl\u00e1me.<\/p>\n<p>Tak\u017ee \u00falohou syst\u00e9mu ukl\u00e1d\u00e1n\u00ed dat je ukl\u00e1dat a poskytovat p\u0159\u00edstup k DAT\u016eM s po\u017eadovan\u00fdm v\u00fdkonem. Od t\u011bchto dat tak\u00e9 za\u010dneme.<\/p>\n<h2>\u00dadaje<\/h2>\n<p><\/p>\n<h3>Typ dat<\/h3>\n<p>\nJak\u00e1 data pl\u00e1nujeme ukl\u00e1dat? Velmi d\u016fle\u017eit\u00e1 ot\u00e1zka, kter\u00e1 m\u016f\u017ee vy\u0159adit mnoho \u00falo\u017ei\u0161\u0165 z dal\u0161\u00edho zva\u017eov\u00e1n\u00ed. Nap\u0159\u00edklad pl\u00e1nujeme ukl\u00e1d\u00e1n\u00ed videoz\u00e1znam\u016f a fotografi\u00ed. Okam\u017eit\u011b m\u016f\u017eeme vy\u0159adit syst\u00e9my ur\u010den\u00e9 pro n\u00e1hodn\u00fd p\u0159\u00edstup k mal\u00fdm blok\u016fm, nebo syst\u00e9my s propriet\u00e1rn\u00edmi funkcemi komprese \/ deduplikace. Tyto syst\u00e9my mohou b\u00fdt skv\u011bl\u00e9, nechceme na nich nic zl\u00e9 \u0159\u00edct. Ale v tomto p\u0159\u00edpad\u011b jejich siln\u00e9 str\u00e1nky se stanou naopak slab\u00fdmi (video a fotografie se nekomprimuj\u00ed) nebo v\u00fdrazn\u011b zv\u00fd\u0161\u00ed n\u00e1klady na syst\u00e9m.<\/p>\n<p>A naopak, pokud je c\u00edlov\u00e9 pou\u017eit\u00ed zat\u00ed\u017een\u00e1 transak\u010dn\u00ed datab\u00e1ze, pak skv\u011bl\u00e9 streamovac\u00ed syst\u00e9my pro multim\u00e9dia, schopn\u00e9 vyoutputovat gigabyty za sekundu, budou \u0161patnou volbou.<\/p>\n<h3>Objem dat<\/h3>\n<p>\nKolik dat pl\u00e1nujeme ukl\u00e1dat? Mno\u017estv\u00ed se v\u017edy p\u0159etv\u00e1\u0159\u00ed v kvalitu, na to bychom nem\u011bli nikdy zapom\u00ednat, zvl\u00e1\u0161\u0165 v na\u0161\u00ed dob\u011b exponenci\u00e1ln\u00edho r\u016fstu objemu dat. Syst\u00e9my petabajtov\u00e9 t\u0159\u00eddy ji\u017e nejsou vz\u00e1cnost\u00ed, ale \u010d\u00edm v\u00edce petabajt\u016f objemu, t\u00edm specifickej\u0161\u00ed syst\u00e9m se st\u00e1v\u00e1, a t\u00edm m\u00e9n\u011b obvykl\u00e9 funkcionality syst\u00e9m\u016f s n\u00e1hodn\u00fdm p\u0159\u00edstupem mal\u00e9ho a st\u0159edn\u00edho objemu bude dostupn\u00e9. Prost\u011b proto, \u017ee pouze tabulky statistiky p\u0159\u00edstupu po bloc\u00edch se st\u00e1vaj\u00ed v\u011bt\u0161\u00edmi ne\u017e dostupn\u00e9 mno\u017estv\u00ed opera\u010dn\u00ed pam\u011bti na \u0159adi\u010d\u00edch. Nemluv\u011b o kompresi \/ tieringu. P\u0159edpokl\u00e1dejme, \u017ee chceme p\u0159epnout algoritmus komprese na v\u00fdkonn\u011bj\u0161\u00ed a zkomprimovat 20 petabajt\u016f dat. Kolik to zabere: p\u016fl roku, rok?<\/p>\n<p>Na druhou stranu, pro\u010d stav\u011bt tov\u00e1rnu, pokud je t\u0159eba ukl\u00e1dat a zpracov\u00e1vat 500 GB dat? Pouze 500. Spot\u0159ebitelsk\u00e9 SSD (s n\u00edzk\u00fdm DWPD) takov\u00e9ho objemu stoj\u00ed jen p\u00e1r korun. Pro\u010d k tomu stav\u011bt Fiber Channel a kupovat extern\u00ed \u00falo\u017ei\u0161t\u011b vysok\u00e9 t\u0159\u00eddy za cenu \u017eelezn\u00e9ho mostu?<\/p>\n<p>Jak\u00fd pod\u00edl z celkov\u00e9ho objemu p\u0159edstavuj\u00ed hork\u00e1 data? Jak nerovnom\u011brn\u00e9 je zat\u00ed\u017een\u00ed podle objemu dat? Pr\u00e1v\u011b zde m\u016f\u017ee velmi pomoci technologie v\u00edcestup\u0148ov\u00e9ho ukl\u00e1d\u00e1n\u00ed nebo Flash Cache, pokud je objem hork\u00fdch dat zanedbateln\u00fd v porovn\u00e1n\u00ed s celkov\u00fdm. Naopak, p\u0159i rovnom\u011brn\u011bj\u0161\u00edm zat\u00ed\u017een\u00ed v cel\u00e9m objemu, co\u017e je b\u011b\u017en\u00e9 v streamovac\u00edch syst\u00e9mech (kamerov\u00e9 sledov\u00e1n\u00ed, n\u011bkter\u00e9 analytick\u00e9 syst\u00e9my), tyto technologie nic nep\u0159inesou a jen zv\u00fd\u0161\u00ed n\u00e1klady \/ slo\u017eitost syst\u00e9mu.<\/p>\n<h3>IS<\/h3>\n<p>\nOpa\u010dn\u00e1 strana dat je informa\u010dn\u00ed syst\u00e9m, kter\u00fd tato data pou\u017e\u00edv\u00e1. IS m\u00e1 soubor po\u017eadavk\u016f, kter\u00e9 jsou odvozeny od dat. Podrobn\u011bji o IS viz \"N\u00e1vrh virtualizovan\u00e9ho datov\u00e9ho centra\".<\/p>\n<h4>Po\u017eadavky na odolnost v\u016f\u010di poruch\u00e1m \/ dostupnost<\/h4>\n<p>Po\u017eadavky na odolnost v\u016f\u010di poruch\u00e1m \/ dostupnost dat jsou odvozeny od IS, kter\u00fd je vyu\u017e\u00edv\u00e1, a vyjad\u0159uj\u00ed se t\u0159emi \u010d\u00edslicemi \u2014 <b>RPO<\/b>, <b>RTO<\/b>, <b>dostupnost<\/b>.<\/p>\n<p><b>Dostupnost <\/b> \u2014 pod\u00edl za dan\u00e9 \u010dasov\u00e9 obdob\u00ed, b\u011bhem kter\u00e9ho jsou data dostupn\u00e1 pro pr\u00e1ci s nimi. Obvykle se vyjad\u0159uje v po\u010dtu dev\u00edtek. Nap\u0159\u00edklad dv\u011b dev\u00edtky za rok znamenaj\u00ed, \u017ee dostupnost je 99 %, tedy je p\u0159\u00edpustn\u00fdch 95 hodin nedostupnosti ro\u010dn\u011b. T\u0159i dev\u00edtky \u2014 9,5 hodiny za rok.<\/p>\n<p>RPO \/ RTO \u2014 to jsou ukazatele nesouhrnn\u00e9, ale pro ka\u017edou ud\u00e1lost (hav\u00e1rii), na rozd\u00edl od dostupnosti.<\/p>\n<p><b>RPO <\/b> \u2014 objem dat ztracen\u00fdch p\u0159i hav\u00e1rii (v hodin\u00e1ch). Nap\u0159\u00edklad, pokud se z\u00e1lohov\u00e1n\u00ed prov\u00e1d\u00ed jednou za den, pak RPO = 24 hodin. Tedy p\u0159i hav\u00e1rii a \u00fapln\u00e9 ztr\u00e1t\u011b \u00falo\u017en\u00e9ho syst\u00e9mu mohou b\u00fdt ztracena data a\u017e do objemu 24 hodin (od okam\u017eiku z\u00e1lohy). Na z\u00e1klad\u011b stanoven\u00e9ho RPO pro IS se nap\u0159\u00edklad vytv\u00e1\u0159\u00ed pravidlo pro z\u00e1lohov\u00e1n\u00ed. Tak\u00e9 na z\u00e1klad\u011b RPO lze pochopit, jak moc je pot\u0159eba synchronn\u00ed \/ asynchronn\u00ed replikace dat.<\/p>\n<p><b>RTO<\/b> \u2014 doba obnoven\u00ed slu\u017eby (p\u0159\u00edstupu k dat\u016fm) po hav\u00e1rii. Na z\u00e1klad\u011b stanoven\u00e9 hodnoty RTO m\u016f\u017eeme posoudit, zda je pot\u0159ebn\u00fd metroklastor, nebo zda posta\u010duje jednosm\u011brn\u00e1 replikace. Je tak\u00e9 pot\u0159eba vyhodnotit, zda je nutn\u00fd v\u00edcestup\u0148ov\u00fd \u00falo\u017en\u00fd syst\u00e9m vy\u0161\u0161\u00ed t\u0159\u00eddy.<\/p>\n<p><img decoding=\"async\" alt=\"Jak vybrat SOD, ani\u017e bych si vyst\u0159elil do nohy\" src=\"\/wp-content\/uploads\/2019\/06\/327166acf29e390fa7454fe66bc4e409.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<\/p>\n<h4>Po\u017eadavky na v\u00fdkon<\/h4>\n<p>\nI kdy\u017e se jedn\u00e1 o zcela z\u0159ejmou ot\u00e1zku, pr\u00e1v\u011b s n\u00ed vznik\u00e1 v\u011bt\u0161ina pot\u00ed\u017e\u00ed. V z\u00e1vislosti na tom, zda ji\u017e m\u00e1te n\u011bjakou infrastrukturu, nebo ne, se budou budovat cesty k z\u00edsk\u00e1n\u00ed nezbytn\u00e9 statistiky.<\/p>\n<p>M\u00e1te ji\u017e \u00falo\u017en\u00e9 za\u0159\u00edzen\u00ed a hled\u00e1te jeho n\u00e1hradu, nebo chcete zakoupit dal\u0161\u00ed pro roz\u0161\u00ed\u0159en\u00ed. Zde je to jednoduch\u00e9. Ch\u00e1pete, jak\u00e9 slu\u017eby ji\u017e m\u00e1te a jak\u00e9 pl\u00e1nujete zav\u00e9st v bl\u00edzk\u00e9 budoucnosti. Na z\u00e1klad\u011b aktu\u00e1ln\u00edch slu\u017eeb m\u00e1te mo\u017enost shrom\u00e1\u017edit statistiku v\u00fdkonnosti. Mus\u00edte se rozhodnout pro aktu\u00e1ln\u00ed po\u010det IOPS a sou\u010dasn\u00e9 latence \u2014 jak\u00e9 jsou tyto hodnoty a zda jsou dostate\u010dn\u00e9 pro va\u0161e \u00fakoly? To lze zjistit jak na samotn\u00e9m \u00falo\u017en\u00e9m syst\u00e9mu, tak na hostitel\u00edch, kter\u00e9 k n\u011bmu jsou p\u0159ipojeny.<\/p>\n<p>Je t\u0159eba se d\u00edvat nejen na aktu\u00e1ln\u00ed z\u00e1t\u011b\u017e, ale i na n\u011bjak\u00e9 obdob\u00ed (nejl\u00e9pe m\u011bs\u00edc). Pod\u00edvejte se na to, jak\u00e9 jsou maxim\u00e1ln\u00ed vrcholy ve dne, jakou z\u00e1t\u011b\u017e vytv\u00e1\u0159\u00ed z\u00e1lohov\u00e1n\u00ed atd. Pokud va\u0161e \u00falo\u017en\u00e9 za\u0159\u00edzen\u00ed nebo software k n\u011bmu neposkytuje kompletn\u00ed sadu t\u011bchto dat, m\u016f\u017eete vyu\u017e\u00edt bezplatn\u00fd RRDtool, kter\u00fd dok\u00e1\u017ee pracovat s v\u011bt\u0161inou nejpopul\u00e1rn\u011bj\u0161\u00edch \u00falo\u017en\u00fdch za\u0159\u00edzen\u00ed a switch\u016f a poskytne v\u00e1m podrobn\u00e9 statistiky o v\u00fdkonnosti. Tak\u00e9 je dobr\u00e9 sledovat z\u00e1t\u011b\u017e na hostitel\u00edch, kter\u00e9 pracuj\u00ed s t\u00edmto \u00falo\u017en\u00fdm za\u0159\u00edzen\u00edm, konkr\u00e9tn\u011b podle virtu\u00e1ln\u00edch stroj\u016f nebo podle toho, co p\u0159esn\u011b na dan\u00e9m hostiteli b\u011b\u017e\u00ed.<\/p>\n<p><img decoding=\"async\" alt=\"Jak vybrat SOD, ani\u017e bych si vyst\u0159elil do nohy\" src=\"\/wp-content\/uploads\/2019\/06\/a0db9ec82e8ab5282e7af5d50e02f281.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nJe t\u0159eba vyzdvihnout, \u017ee pokud se latence na svazku a datastoru, kter\u00fd se nach\u00e1z\u00ed na tomto svazku, v\u00fdrazn\u011b li\u0161\u00ed \u2014 m\u011bli byste se zam\u011b\u0159it na svou SAN s\u00ed\u0165, je vysok\u00e1 pravd\u011bpodobnost, \u017ee s n\u00ed jsou probl\u00e9my, a ne\u017e zakoup\u00edte nov\u00fd syst\u00e9m, stoj\u00ed za to se t\u00edmto probl\u00e9mem zab\u00fdvat, proto\u017ee je velmi pravd\u011bpodobn\u00e9, \u017ee zv\u00fd\u0161\u00edte v\u00fdkon aktu\u00e1ln\u00edho syst\u00e9mu.<\/p>\n<p>Budujete infrastrukturu od nuly, nebo kupujete syst\u00e9m pro n\u011bjakou novou slu\u017ebu, o kter\u00e9 nev\u00edte, jak\u00e9 bude zat\u00ed\u017een\u00ed. Zde je n\u011bkolik mo\u017enost\u00ed: promluvit si s kolegy na specializovan\u00fdch zdroj\u00edch, abyste se pokusili zjistit a p\u0159edpov\u011bd\u011bt z\u00e1t\u011b\u017e, obr\u00e1tit se na integr\u00e1tora, kter\u00fd m\u00e1 zku\u0161enosti s implementac\u00ed podobn\u00fdch slu\u017eeb a kter\u00fd v\u00e1m m\u016f\u017ee vypo\u010d\u00edtat zat\u00ed\u017een\u00ed. A t\u0159et\u00ed mo\u017enost (obvykle nejn\u00e1ro\u010dn\u011bj\u0161\u00ed, zejm\u00e9na pokud se jedn\u00e1 o vlastn\u00ed nebo vz\u00e1cn\u00e9 aplikace) se pokusit zjistit v\u00fdkonov\u00e9 po\u017eadavky u v\u00fdvoj\u00e1\u0159\u016f syst\u00e9mu.<\/p>\n<p>A, a d\u00e1vejte pozor, nejvhodn\u011bj\u0161\u00ed variantou z pohledu praktick\u00e9ho pou\u017eit\u00ed je pilot na aktu\u00e1ln\u00edm za\u0159\u00edzen\u00ed nebo za\u0159\u00edzen\u00ed poskytnut\u00e9m k testov\u00e1n\u00ed dodavatelem \/ integr\u00e1torem.<\/p>\n<h4>Speci\u00e1ln\u00ed po\u017eadavky<\/h4>\n<p>\nSpeci\u00e1ln\u00ed po\u017eadavky zahrnuj\u00ed v\u0161e, co nespad\u00e1 pod po\u017eadavky na v\u00fdkon, odolnost a funk\u010dnost p\u0159i zpracov\u00e1n\u00ed a poskytov\u00e1n\u00ed dat.<\/p>\n<p>Jedn\u00edm z nejjednodu\u0161\u0161\u00edch speci\u00e1ln\u00edch po\u017eadavk\u016f na syst\u00e9m ukl\u00e1d\u00e1n\u00ed dat lze nazvat \u201eodstraniteln\u00e9 informa\u010dn\u00ed nosi\u010de\u201c. Je z\u0159ejm\u00e9, \u017ee tento syst\u00e9m ukl\u00e1d\u00e1n\u00ed dat mus\u00ed zahrnovat p\u00e1skovou knihovnu nebo prost\u011b streamera, na kter\u00fd se ukl\u00e1d\u00e1 z\u00e1loha. Pot\u00e9 speci\u00e1ln\u011b vy\u0161kolen\u00fd \u010dlov\u011bk podep\u00ed\u0161e p\u00e1sek a hrd\u011b ho nese do speci\u00e1ln\u00ed trezoru.<br \/>\nDal\u0161\u00edm p\u0159\u00edkladem speci\u00e1ln\u00edho po\u017eadavku je ochrana proti n\u00e1raz\u016fm.<\/p>\n<h2>Kde<\/h2>\n<p>\nDruh\u00fdm hlavn\u00edm faktorem p\u0159i v\u00fdb\u011bru konkr\u00e9tn\u00edho S\u0158D je informace o tom, KDE bude toto S\u0158D um\u00edst\u011bno. Od geografick\u00fdch nebo klimatick\u00fdch podm\u00ednek a\u017e po person\u00e1l.<\/p>\n<h3>Objednatel<\/h3>\n<p>\nPro koho je tento S\u0158D pl\u00e1nov\u00e1n? Ot\u00e1zka m\u00e1 n\u00e1sleduj\u00edc\u00ed opodstatn\u011bn\u00ed:<\/p>\n<p><b>St\u00e1tn\u00ed objednatel \/ komer\u010dn\u00ed.<\/b><br \/>\nKomer\u010dn\u00ed objednatel nem\u00e1 \u017e\u00e1dn\u00e1 omezen\u00ed a ani nen\u00ed povinen vyhla\u0161ovat ve\u0159ejn\u00e9 sout\u011b\u017ee, krom\u011b vlastn\u00edch intern\u00edch p\u0159edpis\u016f. <\/p>\n<p>St\u00e1tn\u00ed objednatel \u2013 to je jin\u00e1 z\u00e1le\u017eitost. 44. z\u00e1kon a dal\u0161\u00ed v\u00fdhody s tendry a technick\u00fdmi specifikacemi, kter\u00e9 mohou b\u00fdt napadnuty.<\/p>\n<p><b>Objednatel pod sankcemi<\/b><br \/>\nTady je ot\u00e1zka velmi jednoduch\u00e1 \u2013 v\u00fdb\u011br je omezen pouze na nab\u00eddky dostupn\u00e9 pro tohoto objednatele.<\/p>\n<p><b>Intern\u00ed p\u0159edpisy \/ povolen\u00ed k n\u00e1kupu od dodavatel\u016f \/ modely<\/b><br \/>\nOt\u00e1zka je tak\u00e9 velmi jednoduch\u00e1, ale je pot\u0159eba ji m\u00edt na pam\u011bti.<\/p>\n<h3>Kde fyzicky<\/h3>\n<p>\nV t\u00e9to \u010d\u00e1sti zkoum\u00e1me v\u0161echny ot\u00e1zky t\u00fdkaj\u00edc\u00ed se geografie, komunika\u010dn\u00edch kan\u00e1l\u016f a mikroklimatu v m\u00edstnosti, kde je syst\u00e9m um\u00edst\u011bn.<\/p>\n<h4>Person\u00e1l<\/h4>\n<p>\nKdo bude pracovat s t\u00edmto S\u0158D? To je stejn\u011b d\u016fle\u017eit\u00e9, jako to, co S\u0158D skute\u010dn\u011b um\u00ed.<br \/>\nA\u0165 je S\u0158D od dodavatele A jakkoli perspektivn\u00ed, skv\u011bl\u00e9 a \u00fa\u017easn\u00e9, ned\u00e1v\u00e1 smysl ji nasazovat, pokud person\u00e1l um\u00ed pracovat pouze s dodavatelem B a dal\u0161\u00ed n\u00e1kupy a trval\u00e1 spolupr\u00e1ce s A se nepl\u00e1nuj\u00ed.<\/p>\n<p>A samoz\u0159ejm\u011b, dal\u0161\u00ed ot\u00e1zka je, jak dostupn\u00fd je kvalifikovan\u00fd person\u00e1l p\u0159\u00edmo v dan\u00e9 spole\u010dnosti a potenci\u00e1ln\u011b na trhu pr\u00e1ce v t\u00e9to geografick\u00e9 oblasti. Pro regiony m\u016f\u017ee m\u00edt velk\u00fd v\u00fdznam v\u00fdb\u011br TZS s jednoduch\u00fdmi rozhran\u00edmi nebo mo\u017enost\u00ed vzd\u00e1len\u00e9ho centr\u00e1ln\u00edho \u0159\u00edzen\u00ed. Jinak se m\u016f\u017ee v ur\u010dit\u00e9m okam\u017eiku st\u00e1t nesm\u00edrn\u011b bolestiv\u00e9. Internet je pln\u00fd p\u0159\u00edb\u011bh\u016f o tom, jak nov\u00fd zam\u011bstnanec, v\u010derej\u0161\u00ed student, nastavoval n\u011bco tak, \u017ee cel\u00e1 firma zkolabovala.<\/p>\n<p><img decoding=\"async\" alt=\"Jak vybrat SOD, ani\u017e bych si vyst\u0159elil do nohy\" src=\"\/wp-content\/uploads\/2019\/06\/5feeb5b13119c87d6b516d160d801129.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<\/p>\n<h4>Prost\u0159ed\u00ed<\/h4>\n<p>\nNo a samoz\u0159ejm\u011b je d\u016fle\u017eit\u00e1 ot\u00e1zka \u2014 v jak\u00e9m prost\u0159ed\u00ed bude tato TZS fungovat. <\/p>\n<ul>\n<li>Co s nap\u00e1jen\u00edm \/ chlazen\u00edm?<\/li>\n<li>Jak\u00e9 p\u0159ipojen\u00ed<\/li>\n<li>Kam bude nainstalov\u00e1na<\/li>\n<li>A tak d\u00e1le.<\/li>\n<\/ul>\n<p>\n\u010casto jsou tyto ot\u00e1zky pova\u017eov\u00e1ny za samoz\u0159ejm\u00e9 a nen\u00ed jimi zvl\u00e1\u0161\u0165 zab\u00fdv\u00e1no, ale n\u011bkdy pr\u00e1v\u011b tyto ot\u00e1zky mohou v\u0161echno p\u0159evr\u00e1tit naruby.<\/p>\n<h2>Co<\/h2>\n<p><\/p>\n<h3>dodavatel<\/h3>\n<p>\nK dne\u0161n\u00edmu dni (polovina roku 2019) lze rusk\u00fd trh TZS rozd\u011blit do p\u0159ibli\u017en\u011b 5 kategori\u00ed:<\/p>\n<ol>\n<li>Prvn\u00ed divize \u2014 zaveden\u00e9 spole\u010dnosti s \u0161irokou nab\u00eddkou od nejjednodu\u0161\u0161\u00edch diskov\u00fdch pol\u00ed po hi-end (HPE, DellEMC, Hitachi, NetApp, IBM \/ Lenovo)<\/li>\n<li>Druh\u00e1 divize \u2014 spole\u010dnosti s omezen\u00fdm sortimentem, ni\u0161ov\u00ed hr\u00e1\u010di, v\u00e1\u017en\u00ed prodejci SDS nebo nov\u00e1\u010dci (Fujitsu, Datacore, Infinidat, Huawei, Pure atd.)<\/li>\n<li>T\u0159et\u00ed divize \u2014 ni\u0161ov\u00e1 \u0159e\u0161en\u00ed n\u00edzk\u00e9 \u00farovn\u011b, levn\u00fd SDS, DIY \u0159e\u0161en\u00ed na ceph a jin\u00fdch otev\u0159en\u00fdch projektech (Infortrend, Starwind atd.)<\/li>\n<li>SOHO segment \u2014 mal\u00e9 a super mal\u00e9 TZS na \u00farovni dom\u00e1cnost \/ mal\u00e1 kancel\u00e1\u0159 (Synology, QNAP atd.)<\/li>\n<li>Importovan\u00e9 TZS \u2014 sem spadaj\u00ed jak hardware prvn\u00ed divize s p\u0159elepen\u00fdmi etiketami, tak vz\u00e1cn\u00ed z\u00e1stupci druh\u00e9 (RAIDIX, d\u00e1me jim kredit za druhou), ale v\u011bt\u0161inou to je t\u0159et\u00ed divize (Aerodisk, Baum, Depo atd.)<\/li>\n<\/ol>\n<p>\nRozd\u011blen\u00ed je dost podm\u00edn\u011bn\u00e9 a rozhodn\u011b neznamen\u00e1, \u017ee t\u0159et\u00ed nebo SOHO segmenty jsou \u0161patn\u00e9 a nelze je pou\u017e\u00edvat. V specifick\u00fdch projektech s jasn\u011b definovan\u00fdm souborem dat a profilem zat\u00ed\u017een\u00ed mohou fungovat velmi dob\u0159e, daleko p\u0159ekon\u00e1vaj\u00edc\u00ed prvn\u00ed divizi co do pom\u011bru cena\/kvalita. Je d\u016fle\u017eit\u00e9 nejprve si ujasnit \u00fakoly, perspektivy r\u016fstu, pot\u0159ebnou funkcionalitu \u2014 a pak v\u00e1m Synology bude slou\u017eit v\u011brn\u011b, a vlasy budou jemn\u00e9 a hedv\u00e1bn\u00e9.<\/p>\n<p>Jedn\u00edm z d\u016fle\u017eit\u00fdch faktor\u016f p\u0159i v\u00fdb\u011bru dodavatele je aktu\u00e1ln\u00ed prost\u0159ed\u00ed. Kolik a jak\u00e9 \u00falo\u017ei\u0161t\u011b m\u00e1te ji\u017e k dispozici, s jak\u00fdmi syst\u00e9my dok\u00e1\u017eou va\u0161i in\u017een\u00fd\u0159i pracovat. Pot\u0159ebujete dal\u0161\u00edho dodavatele, dal\u0161\u00ed kontaktn\u00ed osobu, nebo budete postupn\u011b migrovat ve\u0161kerou z\u00e1t\u011b\u017e z dodavatele A na dodavatele B?<\/p>\n<p>Nen\u00ed t\u0159eba vytv\u00e1\u0159et entity nad r\u00e1mec nutnosti.<\/p>\n<h3>iSCSI \/ FC \/ File<\/h3>\n<p>\nO problematice p\u0159\u00edstupov\u00fdch protokol\u016f neexistuje jednotn\u00fd n\u00e1zor mezi in\u017een\u00fdry, a spory p\u0159ipom\u00ednaj\u00ed sp\u00ed\u0161e teologick\u00e9 diskuse ne\u017e in\u017een\u00fdrsk\u00e9. Obecn\u011b lze v\u0161ak uv\u00e9st n\u00e1sleduj\u00edc\u00ed body:<\/p>\n<p><b>FCoE<\/b> je sp\u00ed\u0161e mrtv\u00e1 ne\u017e \u017eiv\u00e1.<\/p>\n<p><b>FC vs iSCSI<\/b>. Jednou z kl\u00ed\u010dov\u00fdch v\u00fdhod FC v roce 2019 oproti IP \u00falo\u017ei\u0161t\u00edm, vyhrazen\u00e9 s\u00edti pro p\u0159\u00edstup k dat\u016fm, je vyv\u00e1\u017eena vyhrazenou IP s\u00edt\u00ed. Glob\u00e1ln\u00ed v\u00fdhody FC oproti IP s\u00edt\u00edm neexistuj\u00ed a na IP lze budovat \u00falo\u017ei\u0161t\u011b jak\u00e9koliv \u00farovn\u011b z\u00e1t\u011b\u017ee, v\u010detn\u011b syst\u00e9m\u016f pro t\u011b\u017ek\u00e9 datab\u00e1zov\u00e9 aplikace pro velkou banku. Na druh\u00e9 stran\u011b se FC nevydalo nahoru ji\u017e n\u011bkolik let, ale st\u00e1le mu n\u011bco br\u00e1n\u00ed. Nap\u0159\u00edklad dnes n\u011bkte\u0159\u00ed hr\u00e1\u010di na trhu \u00falo\u017ei\u0161\u0165 aktivn\u011b rozv\u00edjej\u00ed standard NVMEoF. Rozd\u011bl\u00ed se osud FCoE - uk\u00e1\u017ee \u010das.<\/p>\n<p><b>Soubory p\u0159\u00edstup<\/b> tak\u00e9 nen\u00ed nic, co by st\u00e1lo za ignoraci. NFS \/ CIFS se skv\u011ble osv\u011bd\u010duj\u00ed v produktivn\u00edch prost\u0159ed\u00edch a p\u0159i spr\u00e1vn\u00e9m n\u00e1vrhu maj\u00ed stejn\u011b m\u00e1lo v\u00fdhrad jako blokov\u00e9 protokoly.<\/p>\n<h3>Hybridn\u00ed \/ All Flash Array<\/h3>\n<p>\nKlasick\u00e1 \u00falo\u017ei\u0161t\u011b jsou dvou typ\u016f:<\/p>\n<ol>\n<li>AFA (All Flash Array) - syst\u00e9my optimalizovan\u00e9 pro pou\u017eit\u00ed SSD.<\/li>\n<li>Hybridn\u00ed - umo\u017e\u0148uj\u00ed pou\u017e\u00edv\u00e1n\u00ed jak HDD, tak SSD nebo jejich kombinaci.<\/li>\n<\/ol>\n<p>\nHlavn\u00edm rozd\u00edlem je podpora technologi\u00ed pro efektivitu ukl\u00e1d\u00e1n\u00ed a maxim\u00e1ln\u00ed \u00farove\u0148 v\u00fdkonu (vysok\u00e9 hodnoty IOPS a n\u00edzk\u00e9 latence). Ob\u011b syst\u00e9my (ve v\u011bt\u0161in\u011b sv\u00fdch model\u016f, s v\u00fdjimkou low-end segmentu) mohou fungovat jako blokov\u00e1 za\u0159\u00edzen\u00ed i jako souborov\u00e1. \u00darove\u0148 syst\u00e9mu ur\u010duje podporovanou funkcionalitu, kter\u00e1 je u ni\u017e\u0161\u00edch model\u016f \u010dasto omezena na minim\u00e1ln\u00ed \u00farove\u0148. Na to je t\u0159eba br\u00e1t z\u0159etel p\u0159i studiu specifikac\u00ed konkr\u00e9tn\u00edho modelu, nikoli pouze mo\u017enost\u00ed cel\u00e9 \u0159ady jako celku. Tak\u00e9 samoz\u0159ejm\u011b od \u00farovn\u011b syst\u00e9mu z\u00e1vis\u00ed jeho technick\u00e9 charakteristiky, jako jsou procesor, objem pam\u011bti, cache, po\u010det a typy port\u016f atd. Z pohledu spr\u00e1vy v\u0161ak AFA od hybridn\u00edch (diskov\u00fdch) syst\u00e9m\u016f li\u0161\u00ed pouze v ot\u00e1zk\u00e1ch implementace mechanism\u016f pr\u00e1ce se SSD disky, a i kdy\u017e pou\u017e\u00edv\u00e1te SSD v hybridn\u00edm syst\u00e9mu, neznamen\u00e1 to, \u017ee dos\u00e1hnete \u00farovn\u011b v\u00fdkonu jako u AFA syst\u00e9mu. Tak\u00e9 ve v\u011bt\u0161in\u011b p\u0159\u00edpad\u016f jsou inline mechanismy efektivn\u00edho ukl\u00e1d\u00e1n\u00ed v hybridn\u00edch syst\u00e9mech vypnut\u00e9 a jejich aktivace vede ke ztr\u00e1t\u011b v\u00fdkonu.<\/p>\n<h3>Speci\u00e1ln\u00ed SDD<\/h3>\n<p>\nKrom\u011b SDD pro obecn\u00e9 \u00fa\u010dely, orientovan\u00fdch p\u0159edev\u0161\u00edm na operativn\u00ed zpracov\u00e1n\u00ed dat, existuj\u00ed speci\u00e1ln\u00ed SDD s kl\u00ed\u010dov\u00fdmi principy, kter\u00e9 se z\u00e1sadn\u011b li\u0161\u00ed od b\u011b\u017en\u00fdch (n\u00edzk\u00e1 latence, mnoho IOPS):<\/p>\n<p><b>M\u00e9dia. <\/b><\/p>\n<p>Tyto syst\u00e9my jsou ur\u010deny pro ukl\u00e1d\u00e1n\u00ed a zpracov\u00e1n\u00ed medi\u00e1ln\u00edch soubor\u016f, kter\u00e9 se vyzna\u010duj\u00ed velk\u00fdm rozm\u011brem. Odpov\u00eddaj\u00edc\u00ed latence se st\u00e1v\u00e1 t\u00e9m\u011b\u0159 nepodstatnou, a na p\u0159edn\u00ed m\u00edsto se dost\u00e1v\u00e1 schopnost odes\u00edlat a p\u0159ij\u00edmat data \u0161irok\u00fdm p\u00e1smem ve v\u00edce paraleln\u00edch toc\u00edch.<\/p>\n<p><b>Deduplika\u010dn\u00ed SDD pro z\u00e1lohy.<\/b><\/p>\n<p>Proto\u017ee z\u00e1lohy se v b\u011b\u017en\u00fdch podm\u00ednk\u00e1ch li\u0161\u00ed minim\u00e1ln\u00ed podobnost\u00ed (pr\u016fm\u011brn\u00e1 z\u00e1loha se od v\u010derej\u0161\u00ed li\u0161\u00ed o 1-2 %), je tato t\u0159\u00edda syst\u00e9m\u016f extr\u00e9mn\u011b efektivn\u00ed p\u0159i balen\u00ed ulo\u017een\u00fdch dat na pom\u011brn\u011b mal\u00e9m mno\u017estv\u00ed fyzick\u00fdch m\u00e9di\u00ed. Nap\u0159\u00edklad, v n\u011bkter\u00fdch p\u0159\u00edpadech mohou dosahovat koeficienty komprese dat a\u017e 200:1.<\/p>\n<p><b>Objektov\u00e9 SDD.<\/b><\/p>\n<p>V t\u011bchto \u00falo\u017en\u00fdch syst\u00e9mech neexistuj\u00ed obvykl\u00e9 svazky s blokov\u00fdm p\u0159\u00edstupem a sd\u00edlen\u00e9 soubory, sp\u00ed\u0161e p\u0159ipom\u00ednaj\u00ed obrovskou datab\u00e1zi. P\u0159\u00edstup k objektu ulo\u017een\u00e9mu v takov\u00e9m syst\u00e9mu se realizuje podle jedine\u010dn\u00e9ho identifik\u00e1toru nebo podle metadat (nap\u0159\u00edklad v\u0161echny objekty form\u00e1tu JPEG, vytvo\u0159en\u00e9 mezi XX-XX-XXXX a YY-YY-YYYY).<\/p>\n<p><b>Compliance syst\u00e9my<\/b>. <\/p>\n<p>Dnes se v Rusku nevyskytuj\u00ed tak \u010dasto, ale zm\u00ednit je stoj\u00ed za to. \u00da\u010delem takov\u00fdch \u00falo\u017en\u00fdch syst\u00e9m\u016f je garantovan\u00e9 ukl\u00e1d\u00e1n\u00ed dat, kter\u00e9 odpov\u00edd\u00e1 bezpe\u010dnostn\u00edm politik\u00e1m nebo po\u017eadavk\u016fm regul\u00e1tor\u016f. V n\u011bkter\u00fdch syst\u00e9mech (nap\u0159\u00edklad EMC Centera) byla implementov\u00e1na funkce z\u00e1kazu maz\u00e1n\u00ed dat \u2014 jakmile je kl\u00ed\u010d oto\u010den a syst\u00e9m p\u0159e\u0161el do tohoto re\u017eimu, ani administr\u00e1tor, ani nikdo jin\u00fd fyzicky nemohou smazat ji\u017e ulo\u017een\u00e1 data.<\/p>\n<h3>Patentovan\u00e9 technologie<\/h3>\n<p><\/p>\n<h4>Flash cache<\/h4>\n<p>\nFlash Cache je obecn\u00fd n\u00e1zev pro v\u0161echny patentovan\u00e9 technologie pou\u017e\u00edv\u00e1n\u00ed flash pam\u011bti jako druh\u00e9 \u00farovn\u011b cache. P\u0159i pou\u017e\u00edv\u00e1n\u00ed flash cache se obvykle po\u010d\u00edt\u00e1 tak, aby se vyrovnala z\u00e1t\u011b\u017e z magnetick\u00fdch disk\u016f, zat\u00edmco vrcholov\u00e1 z\u00e1t\u011b\u017e je obsluhov\u00e1na cache.<\/p>\n<p>P\u0159itom je nutn\u00e9 ch\u00e1pat profil z\u00e1t\u011b\u017ee a m\u00edru lokalizace po\u017eadavk\u016f na bloky \u00falo\u017en\u00fdch svazk\u016f. Flash cache je technologie pro z\u00e1t\u011b\u017ee s vysokou lokalizac\u00ed po\u017eadavk\u016f a je prakticky neaplikovateln\u00e1 pro rovnom\u011brn\u011b zat\u00ed\u017een\u00e9 svazky (nap\u0159\u00edklad pro analytick\u00e9 syst\u00e9my). <\/p>\n<p>Na trhu jsou k dispozici dv\u011b realizace flash cache:<\/p>\n<ul>\n<li>Read Only. V tomto p\u0159\u00edpad\u011b se ukl\u00e1daj\u00ed pouze data pro \u010dten\u00ed, zat\u00edmco z\u00e1pis prob\u00edh\u00e1 p\u0159\u00edmo na disky. N\u011bkte\u0159\u00ed v\u00fdrobci, jako nap\u0159\u00edklad NetApp, tvrd\u00ed, \u017ee z\u00e1pis na jejich \u00falo\u017en\u00fdch syst\u00e9mech prob\u00edh\u00e1 optim\u00e1ln\u011b, a cache nijak nepom\u016f\u017ee.<\/li>\n<li>Read\/Write. Ukl\u00e1d\u00e1 se nejen \u010dten\u00ed, ale i z\u00e1pis, co\u017e umo\u017e\u0148uje bufferovat proud a sn\u00ed\u017eit vliv RAID penalizace, a t\u00edm zv\u00fd\u0161it celkov\u00fd v\u00fdkon pro \u00falo\u017en\u00e9 syst\u00e9my s m\u00e9n\u011b optim\u00e1ln\u00edm mechanizmem z\u00e1pisu.<\/li>\n<\/ul>\n<p><\/p>\n<h4>Tiering<\/h4>\n<p>\nV\u00edce\u00farov\u0148ov\u00e9 ukl\u00e1d\u00e1n\u00ed (tiering) je technologie spojov\u00e1n\u00ed r\u016fzn\u00fdch \u00farovn\u00ed diskov\u00fdch jednotek s rozd\u00edln\u00fdm v\u00fdkonem do jednotn\u00e9ho diskov\u00e9ho poolu, jako nap\u0159\u00edklad SSD a HDD. V p\u0159\u00edpad\u011b v\u00fdrazn\u00e9 nerovnom\u011brnosti p\u0159\u00edstup\u016f k blok\u016fm dat bude syst\u00e9m schopen automaticky vyv\u00e1\u017eit bloky dat, p\u0159i\u010dem\u017e zat\u00ed\u017een\u00e9 p\u0159esune na vysoce v\u00fdkonnou \u00farove\u0148, a chladn\u00e9 na pomalej\u0161\u00ed.<\/p>\n<p>Hybridn\u00ed syst\u00e9my ni\u017e\u0161\u00edch a st\u0159edn\u00edch t\u0159\u00edd vyu\u017e\u00edvaj\u00ed v\u00edcestup\u0148ov\u00e9 ukl\u00e1d\u00e1n\u00ed s p\u0159em\u00eds\u0165ov\u00e1n\u00edm dat mezi \u00farovn\u011bmi podle pl\u00e1nu. Velikost bloku v\u00edcestup\u0148ov\u00e9ho ukl\u00e1d\u00e1n\u00ed u nejlep\u0161\u00edch model\u016f dosahuje 256 MB. Tyto vlastnosti neumo\u017e\u0148uj\u00ed pova\u017eovat technologii v\u00edcestup\u0148ov\u00e9ho ukl\u00e1d\u00e1n\u00ed za technologii zvy\u0161ov\u00e1n\u00ed v\u00fdkonu, jak si mnoz\u00ed myln\u011b mysl\u00ed. V\u00edcestup\u0148ov\u00e9 ukl\u00e1d\u00e1n\u00ed v syst\u00e9mech ni\u017e\u0161\u00ed a st\u0159edn\u00ed t\u0159\u00eddy je technologi\u00ed optimalizace n\u00e1klad\u016f na ukl\u00e1d\u00e1n\u00ed pro syst\u00e9my s v\u00fdraznou nerovnom\u011brnost\u00ed zat\u00ed\u017een\u00ed.<\/p>\n<h4>Sn\u00edmek<\/h4>\n<p>\nKolik bychom o spolehlivosti \u00falo\u017ei\u0161\u0165 ne\u0159ekli, existuje mnoho mo\u017enost\u00ed, jak ztratit data, kter\u00e9 nez\u00e1vis\u00ed na hardwarov\u00fdch probl\u00e9mech. M\u016f\u017ee to b\u00fdt virus, hacker nebo jak\u00e9koliv jin\u00e9 ne\u00famysln\u00e9 smaz\u00e1n\u00ed\/po\u0161kozen\u00ed dat. Z tohoto d\u016fvodu je z\u00e1lohov\u00e1n\u00ed produktivn\u00edch dat ned\u00edlnou sou\u010d\u00e1st\u00ed pr\u00e1ce in\u017een\u00fdra. <\/p>\n<p>Snapshot je sn\u00edmek svazku v ur\u010dit\u00e9m okam\u017eiku. P\u0159i pr\u00e1ci v\u011bt\u0161iny syst\u00e9m\u016f, jako je virtualizace, datab\u00e1ze atd. pot\u0159ebujeme po\u0159\u00eddit takov\u00fd sn\u00edmek, ze kter\u00e9ho budeme kop\u00edrovat data do z\u00e1lohy, zat\u00edmco na\u0161e IS mohou bez obav pokra\u010dovat v pr\u00e1ci s t\u00edmto svazkem. Ale je t\u0159eba si uv\u011bdomit, \u017ee ne v\u0161echny sn\u00edmky jsou stejn\u011b u\u017eite\u010dn\u00e9. R\u016fzn\u00ed dodavatel\u00e9 maj\u00ed r\u016fzn\u00e9 p\u0159\u00edstupy k vytvo\u0159en\u00ed sn\u00edmk\u016f, kter\u00e9 souvisej\u00ed s jejich architekturou.<\/p>\n<p><b>CoW (Copy-On-Write)<\/b>. P\u0159i pokusu o z\u00e1pis bloku dat se jeho p\u016fvodn\u00ed obsah zkop\u00edruje do speci\u00e1ln\u00ed oblasti, po kter\u00e9 prob\u00edh\u00e1 z\u00e1pis norm\u00e1ln\u011b. T\u00edmto se zabr\u00e1n\u00ed po\u0161kozen\u00ed dat uvnit\u0159 sn\u00edmku. Samoz\u0159ejm\u011b v\u0161echny tyto \"parazitn\u00ed\" manipulace s daty zp\u016fsobuj\u00ed dodate\u010dn\u00e9 zat\u00ed\u017een\u00ed \u00falo\u017ei\u0161t\u011b a z tohoto d\u016fvodu dodavatel\u00e9 s podobnou realizac\u00ed nedoporu\u010duj\u00ed pou\u017e\u00edvat v\u00edce ne\u017e deset sn\u00edmk\u016f a na vysoce zat\u00ed\u017een\u00fdch svazc\u00edch je v\u016fbec nepou\u017e\u00edvat.<\/p>\n<p><b>RoW (Redirect-on-Write)<\/b>. V tomto p\u0159\u00edpad\u011b je p\u016fvodn\u00ed svazek p\u0159irozen\u011b zmra\u017een, a p\u0159i pokusu o z\u00e1pis bloku dat \u00falo\u017ei\u0161t\u011b zapisuje data do speci\u00e1ln\u00ed oblasti v voln\u00e9m prostoru, m\u011bn\u00ed um\u00edst\u011bn\u00ed tohoto bloku v tabulce metadat. To umo\u017e\u0148uje sn\u00ed\u017eit po\u010det p\u0159episovac\u00edch operac\u00ed, co\u017e nakonec neutralizuje pokles v\u00fdkonu a odstra\u0148uje omezen\u00ed na sn\u00edmky a jejich mno\u017estv\u00ed.<\/p>\n<p>Snapshots exist in two types concerning applications:<\/p>\n<p><b>Aplikace konzistentn\u00ed<\/b>. P\u0159i vytv\u00e1\u0159en\u00ed snapshotu \u00falo\u017ei\u0161t\u011b vy\u017eaduje agenta v opera\u010dn\u00edm syst\u00e9mu klienta, kter\u00fd nucen\u011b z\u00e1rove\u0148 vypr\u00e1zdn\u00ed diskov\u00e9 cache z pam\u011bti na disk a p\u0159inut\u00ed aplikaci to ud\u011blat. V tomto p\u0159\u00edpad\u011b budou data p\u0159i obnoven\u00ed ze snapshotu konzistentn\u00ed.<\/p>\n<p><b>Konsistentn\u00ed havarijn\u00ed<\/b>. V tomto p\u0159\u00edpad\u011b k ni\u010demu podobn\u00e9mu nedoch\u00e1z\u00ed a snapshot se vytv\u00e1\u0159\u00ed tak, jak je. P\u0159i obnoven\u00ed z takov\u00e9ho snapshotu je situace stejn\u00e1, jako kdyby do\u0161lo k n\u00e1hl\u00e9mu v\u00fdpadku nap\u00e1jen\u00ed a m\u016f\u017ee doj\u00edt k nabyt\u00ed n\u011bkter\u00fdch dat, kter\u00e1 byla v cache a nestihla se dostat na disk. Takov\u00e9 snapshoty jsou jednodu\u0161\u0161\u00ed na realizaci a nezp\u016fsobuj\u00ed pokles v\u00fdkonu aplikac\u00ed, ale jsou m\u00e9n\u011b spolehliv\u00e9. <\/p>\n<p>Pro\u010d jsou snapshoty pot\u0159ebn\u00e9 v syst\u00e9mech pro ukl\u00e1d\u00e1n\u00ed dat? <\/p>\n<ul>\n<li>Bezagentn\u00ed z\u00e1lohov\u00e1n\u00ed p\u0159\u00edmo z \u00falo\u017ei\u0161t\u011b<\/li>\n<li>Vytv\u00e1\u0159en\u00ed testovac\u00edch prost\u0159ed\u00ed na z\u00e1klad\u011b re\u00e1ln\u00fdch dat<\/li>\n<li>V p\u0159\u00edpad\u011b sd\u00edlen\u00fdch \u00falo\u017ei\u0161\u0165 lze vyu\u017e\u00edt pro vytv\u00e1\u0159en\u00ed prost\u0159ed\u00ed VDI pomoc\u00ed snapshot\u016f \u00falo\u017ei\u0161t\u011b m\u00edsto hypervisoru<\/li>\n<li>Zaji\u0161t\u011bn\u00ed n\u00edzk\u00fdch RPO vytv\u00e1\u0159en\u00edm snapshot\u016f v pl\u00e1novan\u00fdch intervalech mnohem \u010dast\u011bji, ne\u017e je frekvence z\u00e1lohov\u00e1n\u00ed<\/li>\n<\/ul>\n<p><\/p>\n<h4>Klonov\u00e1n\u00ed<\/h4>\n<p>\nKlonov\u00e1n\u00ed objemu funguje na podobn\u00e9m principu jako snapshoty, ale slou\u017e\u00ed nejen pro \u010dten\u00ed dat, ale pro plnohodnotnou pr\u00e1ci s nimi. M\u00e1me mo\u017enost z\u00edskat p\u0159esnou kopii na\u0161eho objemu se v\u0161emi daty na n\u011bm, ani\u017e bychom vytv\u00e1\u0159eli fyzickou kopii, co\u017e umo\u017en\u00ed u\u0161et\u0159it m\u00edsto. Klonov\u00e1n\u00ed objem\u016f se obvykle pou\u017e\u00edv\u00e1 v Test&amp;Dev nebo pokud chcete zkontrolovat funk\u010dnost n\u011bjak\u00fdch aktualizac\u00ed ve va\u0161em IS. Klonov\u00e1n\u00ed to umo\u017en\u00ed ud\u011blat co nejrychleji a ekonomicky z hlediska diskov\u00fdch zdroj\u016f, proto\u017ee budou zaps\u00e1ny pouze zm\u011bn\u011bn\u00e9 bloky dat.<\/p>\n<h4>Replikace \/ \u017eurn\u00e1lov\u00e1n\u00ed<\/h4>\n<p>\nReplikace je mechanismus pro vytv\u00e1\u0159en\u00ed kopi\u00ed dat na jin\u00e9m fyzick\u00e9m \u00falo\u017ei\u0161ti. Obvykle existuje propriet\u00e1rn\u00ed technologie od ka\u017ed\u00e9ho dodavatele, kter\u00e1 funguje pouze v r\u00e1mci jeho vlastn\u00ed \u0159ady. Existuj\u00ed v\u0161ak i t\u0159et\u00ed strany, kter\u00e9 funguj\u00ed, v\u010detn\u011b t\u011bch, kter\u00e9 operuj\u00ed na \u00farovni hypervisoru, jako nap\u0159\u00edklad VMware vSphere Replication.<\/p>\n<p>Funkcionalita propriet\u00e1rn\u00edch technologi\u00ed a jejich snadnost pou\u017eit\u00ed obvykle v\u00fdrazn\u011b p\u0159evy\u0161uj\u00ed univerz\u00e1ln\u00ed, ale jsou nevhodn\u00e9, kdy\u017e nap\u0159\u00edklad pot\u0159ebujete prov\u00e9st replikaci z NetApp na HP MSA.<\/p>\n<p>Replikace se d\u011bl\u00ed na dva podtypy:<\/p>\n<p><b>Synchronn\u00ed<\/b>. P\u0159i synchronn\u00ed replikaci je operace z\u00e1pisu okam\u017eit\u011b p\u0159enesena na druh\u00e9 \u00falo\u017ei\u0161t\u011b a nen\u00ed potvrzena, dokud vzd\u00e1len\u00e9 \u00falo\u017ei\u0161t\u011b nepotvrd\u00ed \u00fasp\u011b\u0161n\u00e9 proveden\u00ed. T\u00edm se zvy\u0161uje latence p\u0159\u00edstupu, ale m\u00e1me p\u0159esnou zrcadlovou kopii dat. Tedy RPO = 0 v p\u0159\u00edpad\u011b ztr\u00e1ty hlavn\u00edho \u00falo\u017ei\u0161t\u011b. <\/p>\n<p><b>Asynchronn\u00ed<\/b>. Z\u00e1pisov\u00e9 operace se prov\u00e1d\u011bj\u00ed pouze na hlavn\u00edm \u00falo\u017ei\u0161ti a jsou okam\u017eit\u011b potvrzeny, zat\u00edmco se hromad\u00ed v pam\u011bti pro d\u00e1vkov\u00fd p\u0159enos na vzd\u00e1len\u00e9 \u00falo\u017ei\u0161t\u011b. Tento typ replikace je relevantn\u00ed pro m\u00e9n\u011b cenn\u00e1 data, nebo pro kan\u00e1ly s n\u00edzkou propustnost\u00ed \u010di s vysokou latenc\u00ed (typick\u00e9 pro vzd\u00e1lenosti p\u0159es 100 km). Odpov\u00eddaj\u00edc\u00ed RPO odpov\u00edd\u00e1 frekvenci d\u00e1vkov\u00e9ho odes\u00edl\u00e1n\u00ed.<\/p>\n<p>\u010casto existuje vedle replikace tak\u00e9 mechanismus <b>\u017eurnalizace<\/b> diskov\u00fdch operac\u00ed. V tomto p\u0159\u00edpad\u011b je vyhrazen zvl\u00e1\u0161tn\u00ed prostor pro \u017eurnalizaci a uchov\u00e1vaj\u00ed se z\u00e1pisov\u00e9 operace ur\u010dit\u00e9 hloubky v \u010dase, nebo omezen\u00e9 objemem \u017eurn\u00e1lu. Pro n\u011bkter\u00e9 propriet\u00e1rn\u00ed technologie, jako je nap\u0159\u00edklad EMC RecoverPoint, existuje integrace se syst\u00e9mov\u00fdm softwarem, kter\u00e1 umo\u017e\u0148uje p\u0159ipojit konkr\u00e9tn\u00ed z\u00e1lo\u017eky k ur\u010dit\u00e9mu z\u00e1pisu v \u017eurn\u00e1lu. D\u00edky tomu je mo\u017en\u00e9 vr\u00e1tit stav svazku (nebo vytvo\u0159it klon) nejen na 23. dubna ve 11 hodin 59 minut 13 milisekund, ale na okam\u017eik t\u011bsn\u011b p\u0159ed \u201eDROP ALL TABLES; COMMIT\u201c.<\/p>\n<h4>Metro cluster<\/h4>\n<p>\nMetro cluster je technologie, kter\u00e1 umo\u017e\u0148uje vytvo\u0159it obousm\u011brnou synchronn\u00ed replikaci mezi dv\u011bma \u00falo\u017ei\u0161ti tak, \u017ee tato dvojice vypad\u00e1 jako jedno \u00falo\u017ei\u0161t\u011b. Pou\u017e\u00edv\u00e1 se k vytvo\u0159en\u00ed cluster\u016f s geograficky vzd\u00e1len\u00fdmi rameny na metro-vzd\u00e1lenostech (m\u00e9n\u011b ne\u017e 100 km).<\/p>\n<p>P\u0159i pou\u017eit\u00ed v prost\u0159ed\u00ed virtualizace umo\u017e\u0148uje metrocluster vytvo\u0159it datastore s virtu\u00e1ln\u00edmi stroji, kter\u00fd je mo\u017en\u00e9 zapisovat p\u0159\u00edmo z obou datov\u00fdch center. V tomto p\u0159\u00edpad\u011b se vytv\u00e1\u0159\u00ed cluster na \u00farovni hypervisor\u016f, sest\u00e1vaj\u00edc\u00ed z hostitel\u016f v r\u016fzn\u00fdch fyzick\u00fdch datov\u00fdch centrech, p\u0159ipojen\u00fd k tomuto datastore. To umo\u017e\u0148uje n\u00e1sleduj\u00edc\u00ed:<\/p>\n<ul>\n<li>Pln\u00e1 automatizace procesu obnovy po hav\u00e1rii jednoho z datov\u00fdch center. Bez jak\u00fdchkoliv dodate\u010dn\u00fdch prost\u0159edk\u016f budou v\u0161echny VM, kter\u00e9 pracovaly v mrtv\u00e9m datov\u00e9m centru, automaticky restartov\u00e1ny v zb\u00fdvaj\u00edc\u00edm. RTO = \u010dasov\u00fd limit clusteru vysok\u00e9 dostupnosti (15 sekund pro VMware) + \u010das pot\u0159ebn\u00fd k na\u010dten\u00ed opera\u010dn\u00edho syst\u00e9mu a spu\u0161t\u011bn\u00ed slu\u017eeb.<\/li>\n<li>Vyh\u00fdb\u00e1n\u00ed se hav\u00e1ri\u00edm. Pokud jsou pl\u00e1nov\u00e1ny pr\u00e1ce na nap\u00e1jen\u00ed v datov\u00e9m centru 1, m\u00e1me mo\u017enost migrovat celou d\u016fle\u017eitou z\u00e1t\u011b\u017e do datov\u00e9ho centra 2 bez p\u0159eru\u0161en\u00ed, a to je\u0161t\u011b p\u0159ed zah\u00e1jen\u00edm prac\u00ed.<\/li>\n<\/ul>\n<p><\/p>\n<h4>Virtualizace<\/h4>\n<p>\nVirtualizace SDD \u2014 to je technicky vyu\u017eit\u00ed objem\u016f z jin\u00e9 SDD jako disk\u016f. SDD-virtualiz\u00e1tor m\u016f\u017ee jednodu\u0161e p\u0159esm\u011brovat ciz\u00ed objem k u\u017eivateli jako sv\u016fj, nav\u00edc ho zrcadl\u00edc na dal\u0161\u00ed SDD, nebo dokonce vytvo\u0159it RAID z extern\u00edch objem\u016f.<br \/>\nKlasick\u00e9 p\u0159\u00edklady ve t\u0159\u00edd\u011b virtualizace SDD \u2014 to jsou EMC VPLEX a IBM SVC. A samoz\u0159ejm\u011b SDD s funkc\u00ed virtualizace \u2014 NetApp, Hitachi, IBM \/ Lenovo Storwize.<\/p>\n<p>K \u010demu to m\u016f\u017ee b\u00fdt pot\u0159ebn\u00e9?<\/p>\n<ul>\n<li>Z\u00e1lohov\u00e1n\u00ed na \u00farovni SDD. Vytv\u00e1\u0159\u00ed se zrcadlo mezi objemy, p\u0159i\u010dem\u017e jedna polovina m\u016f\u017ee b\u00fdt na HP 3Par a druh\u00e1 na NetApp. A virtualiz\u00e1tor od EMC.<\/li>\n<li>P\u0159enos dat s minim\u00e1ln\u00edm v\u00fdpadkem mezi SDD r\u016fzn\u00fdch v\u00fdrobc\u016f. P\u0159edstavme si, \u017ee data je t\u0159eba migrovat ze star\u00e9ho 3Par, kter\u00fd p\u016fjde k vy\u0159azen\u00ed, na nov\u00fd Dell. V tomto p\u0159\u00edpad\u011b se spot\u0159ebitel\u00e9 odpoj\u00ed od 3Par, objemy se p\u0159esm\u011bruj\u00ed pod VPLEX a znovu se prezentuj\u00ed spot\u0159ebitel\u016fm. Proto\u017ee se na objemu nezm\u011bnilo ani bit, pr\u00e1ce pokra\u010duje. Na pozad\u00ed se spou\u0161t\u00ed proces zrcadlen\u00ed objemu na nov\u00fd Dell, a po dokon\u010den\u00ed se zrcadlo rozbije a 3Par se odpoj\u00ed. <\/li>\n<li>Organizace metrocluster\u016f.<\/li>\n<\/ul>\n<p><\/p>\n<h4>Komprese \/ deduplikace<\/h4>\n<p>\nKomprese a deduplikace \u2014 to jsou technologie, kter\u00e9 v\u00e1m umo\u017e\u0148uj\u00ed \u0161et\u0159it diskov\u00fd prostor na va\u0161\u00ed SDD. Je t\u0159eba hned poznamenat, \u017ee ne v\u0161echna data podl\u00e9haj\u00ed kompresi a\/nebo deduplikaci, z\u00e1rove\u0148 n\u011bkter\u00e9 typy dat se komprimuj\u00ed a deduplikuj\u00ed l\u00e9pe, zat\u00edmco jin\u00e9 naopak. <\/p>\n<p>Komprese a deduplikace jsou dvou typ\u016f:<\/p>\n<p><b>Inline<\/b> \u2014 komprese a deduplikace blok\u016f dat prob\u00edh\u00e1 p\u0159ed jejich z\u00e1pisem na disk. T\u00edmto zp\u016fsobem syst\u00e9m pouze spo\u010d\u00edt\u00e1 hash bloku a porovn\u00e1 jej v tabulce s u\u017e existuj\u00edc\u00edmi. Za prv\u00e9, toto se prov\u00e1d\u00ed rychleji ne\u017e pouh\u00fd z\u00e1pis na disk, a za druh\u00e9, nepl\u00fdtv\u00e1me dal\u0161\u00edm diskov\u00fdm prostorem.<\/p>\n<p><b>Post<\/b> \u2014 kdy\u017e tyto operace prob\u00edhaj\u00ed na ji\u017e zapsan\u00fdch datech, kter\u00e1 se nach\u00e1zej\u00ed na disc\u00edch. Odpov\u00eddaj\u00edc\u00edm zp\u016fsobem jsou data nejprve zaps\u00e1na na disk a teprve pot\u00e9 se po\u010d\u00edt\u00e1 hash a doch\u00e1z\u00ed k odstran\u011bn\u00ed nadbytn\u00fdch blok\u016f a uvoln\u011bn\u00ed diskov\u00fdch zdroj\u016f.<\/p>\n<p>Je t\u0159eba \u0159\u00edci, \u017ee v\u011bt\u0161ina dodavatel\u016f pou\u017e\u00edv\u00e1 oba typy, co\u017e umo\u017e\u0148uje optimalizovat tyto procesy a t\u00edm zv\u00fd\u0161it jejich efektivitu. V\u011bt\u0161ina dodavatel\u016f S\u00daS m\u00e1 k dispozici n\u00e1stroje, kter\u00e9 umo\u017e\u0148uj\u00ed analyzovat va\u0161e datov\u00e9 sady. Tyto n\u00e1stroje funguj\u00ed na stejn\u00e9 logice, kter\u00e1 je implementov\u00e1na tak\u00e9 v S\u00daS, a proto bude odhadovan\u00fd \u00farove\u0148 efektivity shodn\u00e1. Tak\u00e9 bychom nem\u011bli zapom\u00ednat, \u017ee mnoz\u00ed dodavatel\u00e9 maj\u00ed programy z\u00e1ruky efektivity, kter\u00e9 slibuj\u00ed \u00farove\u0148 ne ni\u017e\u0161\u00ed, ne\u017e je uvedeno pro ur\u010dit\u00fd (nebo v\u0161echny) typy dat. A nem\u011bli bychom podce\u0148ovat tento program, proto\u017ee p\u0159i kalkulaci syst\u00e9mu pro sv\u00e9 \u00fakoly, s ohledem na koeficient efektivity konkr\u00e9tn\u00edho syst\u00e9mu, m\u016f\u017eete u\u0161et\u0159it na objemu. Je tak\u00e9 t\u0159eba m\u00edt na pam\u011bti, \u017ee tyto programy jsou navr\u017eeny pro AFA syst\u00e9my, ale d\u00edky n\u00e1kupu men\u0161\u00edho objemu SSD ne\u017e HDD v klasick\u00fdch syst\u00e9mech, to umo\u017en\u00ed sn\u00ed\u017eit jejich cenu, a pokud se nevyrovnaj\u00ed cen\u011b diskov\u00e9ho syst\u00e9mu, tak se k n\u00ed p\u0159ibl\u00ed\u017e\u00ed pom\u011brn\u011b siln\u011b.<\/p>\n<h3>Model<\/h3>\n<p>\nA zde se dost\u00e1v\u00e1me k spr\u00e1vn\u011b polo\u017een\u00e9 ot\u00e1zce. <\/p>\n<p>\u201cNab\u00edzej\u00ed mi dva varianty S\u00daS \u2014 ABC SuperStorage S600 a XYZ HyperOcean 666v4, co byste doporu\u010dil?\u201d<\/p>\n<p>P\u0159ev\u00e1d\u00ed se na \u201cNab\u00edzej\u00ed mi dva varianty S\u00daS \u2014 ABC SuperStorage S600 a XYZ HyperOcean 666v4, co byste doporu\u010dil?<\/p>\n<p>C\u00edlov\u00e1 z\u00e1t\u011b\u017e sm\u00ed\u0161en\u00e9 virtu\u00e1ln\u00ed stroje VMware s konturami produkce \/ testov\u00e1n\u00ed \/ v\u00fdvoje. Test = produk\u010dn\u00edmu. 150 TB na ka\u017ed\u00fd s vrcholovou v\u00fdkonem 80 000 IOPS s blokem 8kb 50% n\u00e1hodn\u00e9ho p\u0159\u00edstupu 80\/20 \u010dten\u00ed-z\u00e1pis. 300 TB na v\u00fdvoj, tam 50 000 IOPS bude sta\u010dit, 80 n\u00e1hodn\u00fd, 80 z\u00e1pis.<\/p>\n<p>Producent p\u0159edpokl\u00e1dan\u011b v metroklastru RPO = 15 minut RTO = 1 hodina, v\u00fdvoj v asynchronn\u00ed replikaci RPO = 3 hodiny, test na jednom m\u00edst\u011b.<\/p>\n<p>Bude 50 TB datab\u00e1ze, bylo by dobr\u00e9 m\u00edt pro n\u011b logging.<\/p>\n<p>M\u00e1me v\u0161ude servery Dell, star\u00e9 \u00falo\u017ei\u0161t\u011b Hitachi, jen tak tak zvl\u00e1daj\u00ed, pl\u00e1nujeme r\u016fst o 50 % z\u00e1t\u011b\u017ee na objemu a v\u00fdkonu.<\/p>\n<p>Jak se \u0159\u00edk\u00e1, ve spr\u00e1vn\u011b formulovan\u00e9 ot\u00e1zce je 80 % odpov\u011bdi.<\/p>\n<h2>Dal\u0161\u00ed informace<\/h2>\n<p>\nS \u010d\u00edm by se m\u011blo d\u00e1le sezn\u00e1mit podle autor\u016f.<\/p>\n<h3>Knihy<\/h3>\n<p><\/p>\n<ul>\n<li>Ol\u00edfer a Olifer \u201ePo\u010d\u00edta\u010dov\u00e9 s\u00edt\u011b\u201c. Kniha pom\u016f\u017ee systematizovat a mo\u017en\u00e1 l\u00e9pe pochopit, jak funguje prost\u0159ed\u00ed p\u0159enosu dat pro IP \/ Ethernet syst\u00e9m\u016f \u00falo\u017ei\u0161t\u011b.<\/li>\n<li>\u201eEMC Information Storage and Management\u201c. Skv\u011bl\u00e1 kniha o z\u00e1kladech \u00falo\u017ei\u0161\u0165, pro\u010d, jak a pro\u010d.<\/li>\n<\/ul>\n<p><\/p>\n<h4>F\u00f3ra a chaty<\/h4>\n<p><\/p>\n<ul>\n<li><noindex><a rel=\"nofollow\" href=\"https:\/\/t.me\/storagediscussions\">Storage Discussions<\/a><\/noindex><\/li>\n<li><noindex><a rel=\"nofollow\" href=\"https:\/\/t.me\/nutanix_russia\">Nutanix \/ IT Russian Discussion Club <\/a><\/noindex><\/li>\n<li><noindex><a rel=\"nofollow\" href=\"https:\/\/t.me\/vmugru\">VMware User Group Russia <\/a><\/noindex><\/li>\n<li><noindex><a rel=\"nofollow\" href=\"https:\/\/t.me\/RussianBackupUserGroup\">Russian Backup User Group<\/a><\/noindex> <\/li>\n<\/ul>\n<p><\/p>\n<h3>Obecn\u00e1 doporu\u010den\u00ed<\/h3>\n<p><\/p>\n<h4>Ceny<\/h4>\n<p>\nPokud jde o ceny \u2014 obecn\u011b se ceny \u00falo\u017ei\u0161\u0165, pokud se objev\u00ed, obvykle jedn\u00e1 o doporu\u010den\u00e9 maloobchodn\u00ed ceny, ze kter\u00e9 ka\u017ed\u00fd z\u00e1kazn\u00edk dost\u00e1v\u00e1 individu\u00e1ln\u00ed slevu. Velikost slevy se skl\u00e1d\u00e1 z mnoha parametr\u016f, tak\u017ee p\u0159edpov\u011bd\u011bt, jakou koncovou cenu dostane pr\u00e1v\u011b va\u0161e spole\u010dnost, bez dotazu k distributorovi je prost\u011b nemo\u017en\u00e9. Nicm\u00e9n\u011b v posledn\u00ed dob\u011b se modely low-end objevuj\u00ed v b\u011b\u017en\u00fdch po\u010d\u00edta\u010dov\u00fdch obchodech, jako nap\u0159\u00edklad. <noindex><a rel=\"nofollow\" href=\"http:\/\/nix.ru\">nix.ru<\/a><\/noindex> nebo <noindex><a rel=\"nofollow\" href=\"http:\/\/xcom-shop.ru\">xcom-shop.ru<\/a><\/noindex>. V nich lze okam\u017eit\u011b zakoupit zaj\u00edmav\u00fd syst\u00e9m za pevnou cenu, jako jak\u00e9koli po\u010d\u00edta\u010dov\u00e9 komponenty.<\/p>\n<p>Je v\u0161ak t\u0159eba okam\u017eit\u011b poznamenat, \u017ee p\u0159\u00edm\u00e9 srovn\u00e1n\u00ed podle TB\/$ nen\u00ed spr\u00e1vn\u00e9. Pokud p\u0159istupujete t\u00edmto zp\u016fsobem, nejlevn\u011bj\u0161\u00edm \u0159e\u0161en\u00edm bude jednoduch\u00e9 JBOD + server, co\u017e nenab\u00eddne tu flexibilitu ani spolehlivost, jakou zaji\u0161\u0165uje plnohodnotn\u00e9, dvou\u0159adi\u010dov\u00e9 \u00falo\u017ei\u0161t\u011b. To v\u016fbec neznamen\u00e1, \u017ee JBOD je hrozn\u00e9 a \u0161patn\u00e9, je jen t\u0159eba velmi jasn\u011b pochopit \u2014 jak a k jak\u00fdm \u00fa\u010del\u016fm budete tento syst\u00e9m pou\u017e\u00edvat. \u010casto lze sly\u0161et, \u017ee v JBOD nen\u00ed co se rozb\u00edt, je tam jen jeden backplane. Nicm\u00e9n\u011b i backplany se mohou porouchat. V\u0161echno se d\u0159\u00edve nebo pozd\u011bji pokaz\u00ed.<\/p>\n<h4>Celkem<\/h4>\n<p>\nSrovn\u00e1vat syst\u00e9my mezi sebou je pot\u0159eba nejen podle ceny, nebo jen podle v\u00fdkonnosti, ale podle souhrnu v\u0161ech ukazatel\u016f.<\/p>\n<p>Kupujte HDD pouze v p\u0159\u00edpad\u011b, \u017ee si jste jisti, \u017ee je opravdu pot\u0159ebujete. Pro n\u00edzk\u00e9 z\u00e1t\u011b\u017ee a neslu\u010diteln\u00e9 typy dat se vyplat\u00ed zv\u00e1\u017eit programy z\u00e1ruky efektivity ukl\u00e1d\u00e1n\u00ed na SSD, kter\u00e9 nyn\u00ed nab\u00edz\u00ed v\u011bt\u0161ina dodavatel\u016f (a skute\u010dn\u011b funguj\u00ed, i v \u010cesku), ale z\u00e1le\u017e\u00ed na aplikac\u00edch a datech, kter\u00e9 budou ulo\u017eeny na tomto \u00falo\u017en\u00e9m syst\u00e9mu.<\/p>\n<p>Nepodl\u00e9hejte pouze cen\u011b. \u010casto se za n\u00ed skr\u00fdv\u00e1 \u0159ada nep\u0159\u00edjemn\u00fdch aspekt\u016f, z nich\u017e jeden popsal Evgenij Elizarov ve sv\u00fdch \u010dl\u00e1nc\u00edch o <noindex><a rel=\"nofollow\" href=\"http:\/\/blog.korphome.ru\/tag\/infortrend\/\">Infortrend<\/a><\/noindex>. A co m\u016f\u017ee nakonec va\u0161e \u00faspora b\u00fdt ve sv\u00e9 podstat\u011b nev\u00fdhodn\u00e1. Nezapom\u00ednejte \u2013 \"kdo \u0161et\u0159\u00ed, dvoj\u00ed plat\u00ed\".<br \/>\n<br \/>Zdroj: habr.com<\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u0412\u0432\u0435\u0434\u0435\u043d\u0438\u0435 \u041f\u0440\u0438\u0448\u043b\u0430 \u043f\u043e\u0440\u0430 \u043f\u043e\u043a\u0443\u043f\u0430\u0442\u044c \u0421\u0425\u0414. \u041a\u0430\u043a\u0443\u044e \u0432\u0437\u044f\u0442\u044c, \u043a\u043e\u0433\u043e \u0441\u043b\u0443\u0448\u0430\u0442\u044c? \u0412\u0435\u043d\u0434\u043e\u0440 \u0410 \u0440\u0430\u0441\u0441\u043a\u0430\u0437\u044b\u0432\u0430\u0435\u0442 \u043f\u0440\u043e \u0432\u0435\u043d\u0434\u043e\u0440\u0430 B, \u0430 \u0435\u0449\u0435 \u0435\u0441\u0442\u044c \u0438\u043d\u0442\u0435\u0433\u0440\u0430\u0442\u043e\u0440 C, \u043a\u043e\u0442\u043e\u0440\u044b\u0439 \u0440\u0430\u0441\u0441\u043a\u0430\u0437\u044b\u0432\u0430\u0435\u0442 \u043e\u0431\u0440\u0430\u0442\u043d\u043e\u0435 \u0438 \u0441\u043e\u0432\u0435\u0442\u0443\u0435\u0442 \u0432\u0435\u043d\u0434\u043e\u0440\u0430 D. \u0412 \u0442\u0430\u043a\u043e\u0439 \u0441\u0438\u0442\u0443\u0430\u0446\u0438\u0438 \u0438 \u0443 \u043e\u043f\u044b\u0442\u043d\u043e\u0433\u043e \u0430\u0440\u0445\u0438\u0442\u0435\u043a\u0442\u043e\u0440\u0430 \u043f\u043e \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u043c \u0445\u0440\u0430\u043d\u0435\u043d\u0438\u044f \u0433\u043e\u043b\u043e\u0432\u0430 \u043f\u043e\u0439\u0434\u0435\u0442 \u043a\u0440\u0443\u0433\u043e\u043c, \u043e\u0441\u043e\u0431\u0435\u043d\u043d\u043e \u0441\u043e \u0432\u0441\u0435\u043c\u0438 \u043d\u043e\u0432\u044b\u043c\u0438 \u0432\u0435\u043d\u0434\u043e\u0440\u0430\u043c\u0438 \u0438 \u043c\u043e\u0434\u043d\u044b\u043c\u0438 \u0441\u0435\u0433\u043e\u0434\u043d\u044f SDS \u0438 \u0433\u0438\u043f\u0435\u0440\u043a\u043e\u043d\u0432\u0435\u0440\u0433\u0435\u043d\u0446\u0438\u0435\u0439. \u0418\u0442\u0430\u043a, \u043a\u0430\u043a \u0436\u0435 \u0432\u043e [&hellip;]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":26807,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[688],"tags":[],"class_list":["post-35801","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-administrirovanie"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.3 - aioseo.com -->\n\t<meta name=\"description\" content=\"\u0412\u0432\u0435\u0434\u0435\u043d\u0438\u0435 \u041f\u0440\u0438\u0448\u043b\u0430 \u043f\u043e\u0440\u0430 \u043f\u043e\u043a\u0443\u043f\u0430\u0442\u044c \u0421\u0425\u0414. \u041a\u0430\u043a\u0443\u044e \u0432\u0437\u044f\u0442\u044c, \u043a\u043e\u0433\u043e \u0441\u043b\u0443\u0448\u0430\u0442\u044c? 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