Ithiyori yeCAP sisiseko sethiyori yeenkqubo ezisasaziweyo. Kakade ke, impikiswano ekhoyo ayipheli: iinkcazelo kuyo azikho mibhalo-ngqangi, kwaye akukho bungqina bungqongqo... Nangona kunjalo, simi ngokuqinileyo kwizikhundla zengqiqo yemihla ngemihla™, siyaqonda ukuba ithiyori iyinyani.
Ekuphela kwento engabonakaliyo yintsingiselo yeleta "P". Xa iqela lahluliwe, lithatha isigqibo sokuba lingaphenduli de kufike ikhoram, okanye libuyisele idatha ekhoyo. Ngokuxhomekeke kwiziphumo zolu khetho, inkqubo ihlelwa njenge-CP okanye i-AP. UCassandra, umzekelo, unokuziphatha nangayiphi na indlela, kuxhomekeke nakwizicwangciso zeqela, kodwa kwiiparamitha zesicelo ngasinye. Kodwa ukuba inkqubo ayikho "P" kwaye iyahlukana, yintoni ke?
Impendulo yalo mbuzo ibingalindelekanga noko: Iqela le-CA alinakwahlulwa.
Loluphi uhlobo lweqela elingenako ukwahlula?
Uphawu oluyimfuneko lweqela elinjalo yinkqubo ekwabelwana ngayo yokugcina idatha. Kwiimeko ezininzi, oku kuthetha ukudibanisa ngaphaya kwe-SAN, ethintela ukusetyenziswa kwezisombululo ze-CA kumashishini amakhulu akwaziyo ukugcina isiseko se-SAN. Ukuze iiseva ezininzi zisebenze ngedatha efanayo, inkqubo yefayile edibeneyo iyafuneka. Iinkqubo zefayile ezinjalo ziyafumaneka kwiiphothifoliyo ze-HPE (CFS), Veritas (VxCFS) kunye ne-IBM (GPFS).
Oracle RAC
I-Real Application Cluster ukhetho lwaqala ukubonakala ngo-2001 ngokukhululwa kwe-Oracle 9i. Kwiqela elinjalo, iimeko ezininzi zeseva zisebenza ngesiseko sedatha esifanayo.
I-Oracle inokusebenza kunye nenkqubo yefayile edibeneyo kunye nesisombululo sayo - i-ASM, i-Automatic Storage Management.
Ikopi nganye igcina ijenali yayo. Intengiselwano iyenziwa kwaye yenziwe ngesihlandlo esinye. Ukuba umzekelo awuphumeleli, enye yeendawo ezisindileyo ze-cluster nodes (imizekelo) ifunda ilog yayo kwaye ibuyisela idatha elahlekileyo - ngaloo ndlela iqinisekisa ukufumaneka.
Zonke iimeko zigcina i-cache yazo, kwaye amaphepha afanayo (iibhloko) anokuba kwii-cache zemizekelo emininzi ngexesha elinye. Ngaphaya koko, ukuba umzekelo omnye ufuna iphepha kwaye likwindawo efihlakeleyo yomnye umzekelo, inokulifumana kummelwane walo usebenzisa i-cache fusion mechanism endaweni yokufunda kwidiski.
Kodwa kwenzeka ntoni ukuba enye yeemeko ifuna ukutshintsha idatha?
Ubuqhetseba be-Oracle kukuba ayinayo inkonzo yokutshixa ezinikeleyo: ukuba umncedisi ufuna ukutshixa umqolo, ke irekhodi lokutshixa libekwe ngqo kwiphepha lememori apho umqolo otshixiweyo ukhoyo. Ngombulelo kule ndlela, i-Oracle yintshatsheli yokusebenza phakathi kwedatha ye-monolithic: inkonzo yokutshixa ayize ibe yingxaki. Kodwa kuqwalaselo lweqela, uyilo olunjalo lunokukhokelela kwitrafikhi yenethiwekhi enkulu kunye nokuvalwa.
Nje ukuba irekhodi itshixiwe, umzekelo wazisa zonke ezinye iimeko ukuba iphepha eligcina loo rekhodi libanjwe kuphela. Ukuba omnye umzekelo ufuna ukutshintsha irekhodi kwiphepha elifanayo, kufuneka lilinde de kube utshintsho lwephepha lwenziwe, oko kukuthi, ulwazi lokutshintsha lubhalwa kwijenali kwidiski (kwaye ukuthengiselana kunokuqhubeka). Kuyenzeka kwakhona ukuba iphepha litshintshwe ngokulandelelana ngeekopi ezininzi, kwaye ke xa ubhala iphepha kwidiski kuya kufuneka ufumanise ukuba ngubani ogcina uguqulelo lwangoku lweli phepha.
Ukuhlaziya ngokungaqhelekanga amaphepha afanayo kwiindawo ezahlukeneyo ze-RAC kubangela ukuba ukusebenza kwedatha yehle kakhulu, ukuya kwindawo apho ukusebenza kweqela kunokuba ngaphantsi kunomzekelo omnye.
Ukusetyenziswa okuchanekileyo kwe-Oracle RAC kukwahlula-hlula ngokwasemzimbeni idatha (umzekelo, usebenzisa i-partitioned table mechanism) kunye nokufikelela kwiseti nganye yezahlulo nge-node ezinikeleyo. Eyona njongo iphambili ye-RAC yayingekuko ukukala okuthe tye, kodwa iqinisekisa ukunyamezela impazamo.
Ukuba i-node iyeka ukuphendula kwi-heartbeat, ke i-node eyifumene kuqala iqala inkqubo yokuvota kwidiski. Ukuba indawo engekhoyo ayiqatshelwanga apha, ke enye yeenodi ithatha uxanduva lokubuyisela idatha:
- “umkhenkce” onke amaphepha abekwindawo efihlakeleyo yenodi engekhoyo;
- ifunda iilog (yenza kwakhona) yendawo elahlekileyo kwaye iphinda isebenzise utshintsho olurekhodiweyo kwezi logs, ngaxeshanye ijonga ukuba ingaba ezinye iindawo zineenguqulelo zamva nje zamaphepha atshintshiweyo;
- ibuyisela umva intengiselwano elindelekileyo.
Ukwenza lula ukutshintsha phakathi kweenodi, i-Oracle inombono wenkonzo - umzekelo obonakalayo. Umzekelo unokukhonza iinkonzo ezininzi, kwaye inkonzo inokuhamba phakathi kweendawo zokuhlala. Umzekelo wesicelo okhonza inxalenye ethile yesiseko sedatha (umzekelo, iqela labaxhasi) lisebenza ngenkonzo enye, kwaye inkonzo enoxanduva lwale nxalenye yesiseko sedatha ihambela kwenye i-node xa i-node ingaphumeleli.
IiNkqubo zeDatha ePure ye-IBM yeeNtengiselwano
Isisombululo se-cluster se-DBMS sivele kwi-portfolio ye-Blue Giant kwi-2009. Ngokwengcamango, ngumlandeli weqela leParallel Sysplex, elakhiwe kwizixhobo "eziqhelekileyo". Kwi-2009, i-DB2 pureScale yakhululwa njenge-software suite, kwaye kwi-2012, i-IBM yanikezela ngesixhobo esibizwa ngokuba yi-Pure Data Systems for Transactions. Akufanele kudideke kunye neNkqubo yeDatha ePure ye-Analytics, engeyonto ngaphandle kweNetezza ebizwa ngokuba yiNetezza.
Ekuboneni kokuqala, i-architecture ecocekileyo ye-pureScale ifana ne-Oracle RAC: ngendlela efanayo, ii-node ezininzi zixhunyiwe kwinkqubo yokugcina idatha eqhelekileyo, kwaye i-node nganye iqhuba umzekelo wayo we-DBMS kunye neendawo zayo zememori kunye nezigodo zokuthengiselana. Kodwa, ngokungafaniyo ne-Oracle, i-DB2 inenkonzo yokutshixa ezinikeleyo emelwe yiseti yeenkqubo ze-db2LLM*. Kwi-cluster configuration, le nkonzo ifakwe kwi-node eyahlukileyo, ebizwa ngokuba yi-coupling facility (CF) kwi-Parallel Sysplex, kunye ne-PowerHA kwi-Pure Data.
I-PowerHA ibonelela ngezi nkonzo zilandelayo:
- umphathi wokutshixa;
- i-cache ye-buffer yehlabathi;
- indawo yonxibelelwano lwenkqubo.
Ukudlulisa idatha ukusuka kwi-PowerHA ukuya kwi-database nodes kunye nomva, ukufikelela kwimemori ekude kusetyenziswa, ngoko ke i-cluster interconnect kufuneka ixhase iprotocol ye-RDMA. I-PureScale inokusebenzisa zombini i-Infiniband kunye ne-RDMA phezu kwe-Ethernet.
Ukuba i-node idinga iphepha, kwaye eli phepha alikho kwi-cache, ngoko i-node icela iphepha kwi-cache yehlabathi, kwaye kuphela xa ingekho, ifunde kwidiski. Ngokungafaniyo ne-Oracle, isicelo siya kuphela kwi-PowerHA, kwaye hayi kwiindawo ezingabamelwane.
Ukuba umzekelo uzakutshintsha umqolo, uyitshixa kwimowudi ekhethekileyo, kunye nephepha apho umqolo ubekwe kwimo ekwabelwana ngayo. Zonke izitshixo zibhaliswe kumphathi wetshixo yehlabathi. Xa intengiselwano igqiba, i-node ithumela umyalezo kumphathi wokutshixa, okhuphela iphepha elilungisiweyo kwi-cache yehlabathi, ukhulula izitshixo, kwaye ungasebenzi iphepha elilungisiweyo kwii-cache zezinye iindawo.
Ukuba iphepha apho umqolo olungisiweyo ukhoyo sele itshixiwe, ngoko ke umphathi wokutshixa uya kufunda iphepha eliguquliweyo kwinkumbulo yenodi elenze utshintsho, khulula isitshixo, ulenze ukungasebenzi kwephepha eliguquliweyo kwiicache zezinye iindawo, kwaye nika isitshixo sephepha kwindawo eceliweyo.
"Ukungcola", oko kukuthi, utshintshile, amaphepha angabhalwa kwidisk zombini ukusuka kwi-node eqhelekileyo kunye ne-PowerHA (castout).
Ukuba enye ye-pureScale nodes ayiphumelelanga, ukubuyiswa kukhawulelwe kuphela kwezo ntengiselwano ezingazange zigqitywe ngexesha lokungaphumeleli: amaphepha alungiswe yiloo node kwiintengiselwano ezigqityiweyo zikwi-cache yehlabathi kwi-PowerHA. I-node iphinda iqale kubumbeko obuncitshisiweyo kwenye yeeseva kwiqela, ibuyisela umva intengiselwano elindelekileyo kwaye ikhuphe izitshixo.
I-PowerHA isebenza kwiiseva ezimbini kwaye i-master node iphinda-phinda imeko yayo ngokulandelelana. Ukuba i-node yokuqala ye-PowerHA iyasilela, iqela liyaqhubeka nokusebenza nge-node yokugcina.
Ngokuqinisekileyo, ukuba ufikelela kwidatha esetyenzisiweyo nge-node enye, ukusebenza ngokubanzi kweqela kuya kuba phezulu. I-PureScale inokuqaphela nokuba indawo ethile yedatha icutshungulwa yi-node enye, kwaye ke zonke izitshixo ezinxulumene naloo ndawo ziya kucutshungulwa kwindawo yendawo ngaphandle kokunxibelelana nePowerHA. Kodwa kamsinya nje ukuba isicelo sizama ukufikelela kule datha ngenye indawo, ukusetyenzwa kwetshixo esembindini kuya kuphinda kuqalise.
Iimvavanyo zangaphakathi ze-IBM kumthwalo we-90% wokufunda kunye ne-10% yokubhala, efana kakhulu nomthwalo wemveliso wehlabathi wangempela, ubonisa ukulinganisa umgca ukuya kwi-128 nodes. Iimeko zovavanyo, ngelishwa, azichazwanga.
HPE NonStop SQL
Ipotfoliyo ye-Hewlett-Packard Enterprise nayo ineqonga layo elifumaneka kakhulu. Eli liqonga le-NonStop, elakhutshwa kwimarike ngo-1976 yiTandem Computers. Kwi-1997, inkampani yafunyanwa yiCompaq, eyathi yadibaniswa neHewlett-Packard kwi-2002.
I-NonStop isetyenziselwa ukwakha izicelo ezibalulekileyo - umzekelo, i-HLR okanye ukusetyenzwa kwekhadi lebhanki. Iqonga linikezelwa ngendlela ye-software kunye ne-hardware complex (isixhobo), esibandakanya ii-nodes ze-computing, inkqubo yokugcina idatha kunye nezixhobo zokunxibelelana. Inethiwekhi ye-ServerNet (kwiinkqubo zanamhlanje - i-Infiniband) isebenza zombini ngokutshintshiselana phakathi kweenodi kunye nokufikelela kwinkqubo yokugcina idatha.
Iinguqulelo zangaphambili zenkqubo zasebenzisa iiprosesa zobunikazi eziye zadityaniswa kunye: yonke imisebenzi yenziwa ngaxeshanye ngamaprosesa amaninzi, kwaye ngokukhawuleza ukuba enye yeeprosesa yenza impazamo, yacinywa, kwaye okwesibini yaqhubeka ukusebenza. Kamva, inkqubo yatshintshela kwiiprosesa eziqhelekileyo (i-MIPS yokuqala, emva koko i-Itanium kwaye ekugqibeleni i-x86), kunye nezinye iindlela zaqala ukusetyenziswa ungqamaniso:
- imiyalezo: inkqubo nganye yenkqubo inewele "lomthunzi", apho inkqubo esebenzayo ithumela rhoqo imiyalezo malunga nobume bayo; ukuba inkqubo engundoqo iyasilela, inkqubo yesithunzi iqala ukusebenza ukusuka kumzuzu ogqitywe ngumyalezo wokugqibela;
- ukuvota: inkqubo yogcino inecandelo elikhethekileyo lehardware elamkela ufikelelo oluninzi olufanayo kwaye lizenze kuphela ukuba ukufikelela kuhambelana; Endaweni yongqamaniso lomzimba, abaqhubekekisi basebenza ngokulinganayo, kwaye iziphumo zomsebenzi wabo zithelekiswa kuphela ngamaxesha e-I/O.
Ukususela ngo-1987, i-DBMS yobudlelwane ibisebenza kwi-platform ye-NonStop - yokuqala ye-SQL / MP, kwaye kamva i-SQL / MX.
I-database yonke yahlulwe yangamacandelo, kwaye inxalenye nganye inoxanduva lwenkqubo yayo yoMphathi weData (DAM). Ibonelela ngokurekhoda kwedatha, i-caching, kunye neendlela zokutshixa. Ukusetyenzwa kwedatha kwenziwa yiNkqubo yoMsebenzi woMsebenzi osebenza kwiindawo ezifanayo njengabaphathi bedatha abahambelanayo. Umcwangcisi weSQL/MX wahlula imisebenzi phakathi kwabenzi bomsebenzi kwaye uhlanganisa iziphumo. Xa kuyimfuneko ukwenza utshintsho ekuvunyelwene ngalo, iprotocol yokuzinikela yamanqanaba amabini ebonelelwa lithala leencwadi leTMF (Transaction Management Facility) iyasetyenziswa.
I-NonStop SQL inokubeka phambili iinkqubo ukuze imibuzo emide yohlalutyo ingaphazamisi ukuphunyezwa kwentengiselwano. Nangona kunjalo, injongo yayo kukusetyenzwa kwentengiselwano emfutshane, kwaye hayi uhlalutyo. Umphuhlisi uqinisekisa ubukho beqela le-NonStop kwinqanaba lee-"nines" ezintlanu, oko kukuthi, ixesha lokuphumla yimizuzu emi-5 kuphela ngonyaka.
SAP-HANA
Ukukhutshwa kokuqala okuzinzileyo kwe-HANA DBMS (1.0) kwenzeka ngoNovemba 2010, kwaye iphakheji ye-SAP ERP yatshintshela kwi-HANA ngoMeyi 2013. Iqonga lisekelwe kubuchwephesha obuthengiweyo: Injini yokukhangela ye-TREX (ukukhangela kwivenkile yekholomu), i-P * TIME DBMS kunye ne-MAX DB.
Igama elithi "HANA" ngokwalo sisishunqulelo, Ukusebenza okuphezulu kwe-Analytical Appliance. Le DBMS inikezelwa ngendlela yekhowudi enokuthi iqhube kuzo naziphi na iiseva ze-x86, nangona kunjalo, ukufakwa kwamashishini kuvunyelwe kuphela kwizixhobo eziqinisekisiweyo. Izisombululo ezifumaneka kwi-HP, Lenovo, Cisco, Dell, Fujitsu, Hitachi, NEC. Olunye uqwalaselo lweLenovo lude luvumele ukusebenza ngaphandle kwe-SAN - indima yenkqubo yogcino eqhelekileyo idlalwa liqela leGPFS kwiidiski zendawo.
Ngokungafani namaqonga adweliswe ngasentla, i-HANA yi-DBMS ekwimemori, oko kukuthi umfanekiso wedatha ophambili ugcinwe kwi-RAM, kwaye kuphela iilogi kunye ne-periodic snapshots zibhalwa kwidiski yokubuyisela kwimeko yentlekele.
I-node ye-cluster ye-HANA nganye inoxanduva lwenxalenye yayo yedatha, kwaye imephu yedatha igcinwe kwicandelo elikhethekileyo - i-Name Server, ebekwe kwi-node yomququzeleli. Idatha ayiphindaphindwa phakathi kweendawo zokuhlala. Ulwazi lokutshixa lukwagcinwa kwindawo nganye, kodwa inkqubo inesixhobo sokujonga i-global deadlock.
Xa umxhasi we-HANA edibanisa kwi-cluster, ikhuphela i-topology yayo kwaye inokufikelela kuyo nayiphi na i-node ngokuthe ngqo, kuxhomekeke kwiyiphi idatha eyifunayo. Ukuba intengiselwano ichaphazela idatha yendawo enye, ngoko inokuphunyezwa kwindawo leyo ndawo, kodwa ukuba idatha yeendawo ezininzi ziyatshintsha, i-node yokuqalisa iqhagamshelana nomnxibelelanisi, evula kwaye ilungelelanise intengiselwano esasaziweyo, iyenze usebenzisa i-node. iprotocol yokuzinikela elungiselelwe izigaba ezibini.
I-node yomnxibelelanisi iphindwe kabini, ngoko ke ukuba umququzeleli uyasilela, i-node yokugcina ngokukhawuleza ithatha indawo. Kodwa ukuba i-node enedatha iyasilela, ke ekuphela kwendlela yokufikelela kwidatha yayo kukuqalisa kwakhona i-node. Njengomthetho, amaqela e-HANA agcina umncedisi osecaleni ukuze uqalise kwakhona i-node elahlekileyo kuyo ngokukhawuleza.
umthombo: www.habr.com