An daɗe da ƙirƙira fasahohi don haɓaka aiki dangane da amfani da SSDs kuma ana amfani da su sosai a cikin tsarin ajiya. Da farko dai, shine amfani da SSD azaman sararin ajiya, wanda yake da tasiri 100%, amma tsada. Saboda haka, ana amfani da fasahar gajiya da caching, inda ake amfani da SSDs kawai don shahararrun bayanan ("zafi"). Tiering yana da kyau ga yanayin dogon lokaci (makonni-makonni) amfani da bayanan "zafi". Caching, akasin haka, na ɗan gajeren lokaci ne (mintuna-awa) amfani. Ana aiwatar da waɗannan zaɓuɓɓukan biyu a cikin tsarin ajiya . A cikin wannan labarin za mu dubi aiwatar da algorithm na biyu - .
Mahimmancin fasahar caching SSD shine amfani da SSDs azaman matsakaicin cache tsakanin rumbun kwamfyuta da RAM mai sarrafawa. Ayyukan SSD, ba shakka, ƙasa da aikin cache na mai sarrafawa, amma ƙarar tsari ne na girma mafi girma. Sabili da haka, muna samun ƙayyadaddun daidaituwa tsakanin sauri da girma.
Alamu don amfani da cache SSD don karantawa:
- Galibin ayyukan karantawa akan ayyukan rubuce-rubuce (mafi yawan al'ada don bayanan bayanai da aikace-aikacen yanar gizo);
- Kasancewar ƙugiya a cikin nau'i na aikin rumbun kwamfutarka;
- Adadin bayanan da ake buƙata bai kai girman cache na SSD ba.
Alamu don amfani da cache na karanta + rubuta SSD iri ɗaya ne, ban da yanayin ayyukan - nau'in gauraye (misali, uwar garken fayil).
Yawancin masu siyar da ajiya suna amfani da cache na SSD mai karantawa kawai a cikin samfuran su. Bambanci na asali Suna ba da damar yin amfani da cache don rubutu kuma. Don kunna aikin caching SSD a cikin tsarin ajiya na QSAN, dole ne ku sayi lasisi daban (wanda aka kawo ta lantarki).
Cache na SSD a cikin XCubeSAN ana aiwatar da shi ta zahiri ta hanyar nau'ikan wuraren waha na cache SSD daban. Za a iya samun har zuwa hudu a cikin tsarin. Kowane tafkin, ba shakka, yana amfani da tsarin sa na SSDs. Kuma riga a cikin kaddarorin faifan faifai mun ƙayyade ko zai yi amfani da tafkin cache kuma wanene. Yin kunnawa da kashe amfani da cache don juzu'i ana iya yin su akan layi ba tare da dakatar da I/O ba. Hakanan zaka iya zafi ƙara SSDs zuwa tafkin kuma cire su daga can. Lokacin ƙirƙirar cache pool na SSD, kuna buƙatar zaɓar yanayin da zai yi aiki a ciki: karanta-kawai ko karanta + rubuta. Ƙungiya ta jiki ta dogara da wannan. Tunda ana iya samun wuraren tafkunan cache da yawa, ayyukansu na iya bambanta (wato tsarin na iya karantawa da karantawa + rubuta wuraren wuraren ajiya a lokaci guda).
Idan aka yi amfani da wurin ajiyar ajiya mai karantawa kawai, zai iya ƙunshi 1-8 SSDs. Fayilolin ba dole ba ne su kasance masu ƙarfi iri ɗaya da mai siyarwa iri ɗaya, saboda an haɗa su zuwa tsarin NRAID+. Ana raba duk SSDs da ke cikin tafkin. Tsarin da kansa yana ƙoƙarin daidaita buƙatun masu shigowa tsakanin duk SSDs don cimma iyakar aiki. Idan ɗaya daga cikin SSDs ya gaza, babu wani mugun abu da zai faru: bayan haka, cache ɗin yana ƙunshe da kwafin bayanan da aka adana akan tsararrun faifai. Kawai adadin cache na SSD zai ragu (ko zama sifili idan amfani da cache na asali na SSD daga tuƙi ɗaya).
Idan an yi amfani da cache don karantawa + rubuta ayyukan, to, adadin SSDs a cikin tafkin ya kamata ya zama mahara biyu, tunda abubuwan da ke ciki suna madubi akan nau'ikan faifai (ana amfani da tsarin NRAID 1+). Kwafi cache ya zama dole saboda yana iya ƙunsar bayanan da ba a rubuta ba tukuna zuwa rumbun kwamfyuta. Kuma a wannan yanayin, gazawar SSD daga wurin ajiyar cache zai haifar da asarar bayanai. A cikin yanayin NRAID 1+, gazawar SSD kawai zai haifar da canja wurin cache zuwa yanayin karantawa kawai, tare da zubar da bayanan da ba a rubuta ba a kan tsararrun faifai. Bayan maye gurbin SSD mara kyau, cache ɗin zai koma yanayin aikinsa na asali. Af, don ƙarin tsaro, zaku iya sanya keɓancewar keɓancewa masu zafi zuwa ma'ajiyar karanta + rubuta.
Lokacin amfani da aikin caching na SSD a cikin XCubeSAN, akwai buƙatu da yawa don adadin ƙwaƙwalwar ajiya na masu sarrafa ajiya: ƙarin ƙwaƙwalwar tsarin, mafi girman tafkin cache zai kasance.
Ba kamar yawancin masana'antun tsarin ajiya ba, waɗanda kawai ke ba da zaɓi don kunna / kashe cache na SSD, QSAN yana ba da ƙarin zaɓuɓɓuka. Musamman, zaku iya zaɓar yanayin aiki na cache dangane da yanayin kaya. Akwai samfuran saiti guda uku waɗanda suka fi kusanci a cikin aikin su zuwa ayyukan da suka dace: bayanai, tsarin fayil, sabis na yanar gizo. Bugu da kari, mai gudanarwa na iya ƙirƙirar bayanin martaba na kansa ta hanyar saita ƙimar sigina da ake buƙata:
- Girman Toshe (Girman Kashe Kashe) - 1/2/4 MB
- Yawan buƙatun karanta toshe don a kwafi shi zuwa ma'ajiyar (Mai yawan-kan-Karanta Ƙarfin) - 1..4
- Adadin buƙatun rubuta toshe domin a kwafi shi zuwa ma'ajiyar (Populate-on-Write Threshold) - 0..4
Ana iya canza bayanan martaba akan tashi, amma, ba shakka, tare da abubuwan da ke cikin sake saitin cache da sabon "dumama".
Idan akai la'akari da ka'idar aiki na cache SSD, zamu iya haskaka manyan ayyukan yayin aiki tare da shi:
Karanta bayanai lokacin da ba a cikin cache ba
- Wata bukata daga mai watsa shiri ta isa wurin mai sarrafawa;
- Tun da waɗanda aka nema ba su cikin cache na SSD, ana karanta su daga rumbun kwamfyuta;
- Ana aika bayanan karantawa ga mai watsa shiri. A lokaci guda, ana bincika don ganin ko waɗannan tubalan suna "zafi";
- Idan eh, to ana kwafi su zuwa cache na SSD don ƙarin amfani.
Karanta bayanai lokacin da yake cikin cache
- Wata bukata daga mai watsa shiri ta isa wurin mai sarrafawa;
- Tun da bayanan da ake buƙata suna cikin ma'ajin SSD, ana karanta shi daga can;
- Ana aika bayanan karantawa ga mai watsa shiri.
Rubutun bayanai lokacin amfani da cache karanta
- Buƙatun rubuta daga mai watsa shiri ya isa wurin mai sarrafawa;
- An rubuta bayanai zuwa rumbun kwamfyuta;
- Ana mayar da martanin da ke nuna nasarar yin rikodi ga mai masaukin baki;
- A lokaci guda kuma, ana bincika ko toshe yana "zafi" (ana kwatanta ma'aunin Ƙarfafa-kan-Rubuta). Idan eh, to ana kwafe shi zuwa cache na SSD don amfani daga baya.
Rubuta bayanai lokacin amfani da cache karanta+ rubuta
- Buƙatun rubuta daga mai watsa shiri ya isa wurin mai sarrafawa;
- An rubuta bayanai zuwa cache na SSD;
- Ana mayar da martanin da ke nuna nasarar yin rikodi ga mai masaukin baki;
- An rubuta bayanai daga cache SSD zuwa rumbun kwamfyuta a bango;
Duba cikin aiki
Gwajin tsayawa
2 sabobin (CPU: 2 x Xeon E5-2620v3 2.4Hz / RAM: 32GB) ana haɗa su ta tashoshin jiragen ruwa guda biyu ta hanyar Fiber Channel 16G kai tsaye zuwa tsarin ajiya na XCubeSAN XS5224D (16GB RAM / mai sarrafawa).
Mun yi amfani da 16 x Seagate Constellation ES, ST500NM0001, 500GB, SAS 6Gb/s, hade a RAID5 (15 + 1), don tsararrun bayanai da 8 x HGST Ultrastar SSD800MH.B, HUSMH8010BSS200, 100AS12Gbs cache
An ƙirƙiri juzu'i 2: ɗaya ga kowane uwar garken.
Gwaji 1. Karatun-kawai SSD cache daga 1-8 SSDs
SSD cache
- Nau'in I/O: Keɓancewa
- Girman Toshe Cache: 4MB
- Ƙofar Jama'a-kan-karanta: 1
- Ƙaddamarwa-kan-rubutu: 0
Tsarin I/O
- Kayan aiki: IOmeter V1.1.0
- Ma'aikata: 1
- Fitaccen (Zururin Queue): 128
- Ƙididdiga masu zuwa: 4KB, 100% Karanta, 100% Random
A ka'idar, yawancin SSDs a cikin tafkin cache, mafi girman aikin. A aikace, an tabbatar da hakan. Ƙaƙƙarwar haɓaka kawai a cikin adadin SSDs tare da ƙananan ƙididdiga ba ya haifar da sakamako mai fashewa.
Gwaji 2. SSD cache a yanayin karanta + rubutu tare da 2-8 SSDs
SSD cache
- Nau'in I/O: Keɓancewa
- Girman Toshe Cache: 4MB
- Ƙofar Jama'a-kan-karanta: 1
- Ƙaddamarwa-kan-rubutu: 1
Tsarin I/O
- Kayan aiki: IOmeter V1.1.0
- Ma'aikata: 1
- Fitaccen (Zururin Queue): 128
- Ƙididdiga masu zuwa: 4KB, 100% Rubuta, 100% Random
Sakamakon iri ɗaya: haɓaka aikin fashewa da haɓakawa yayin da adadin SSDs ke ƙaruwa.
A cikin gwaje-gwajen guda biyu, adadin bayanan aiki bai kai jimlar girman cache ba. Don haka, bayan lokaci, an kwafi duk tubalan zuwa ma'ajiyar. Kuma aikin, a zahiri, an riga an aiwatar da shi tare da SSDs, a zahiri ba tare da shafar rumbun kwamfyuta ba. Manufar waɗannan gwaje-gwajen shine don nuna a fili tasirin dumama cache da haɓaka aikin sa dangane da adadin SSDs.
Yanzu bari mu dawo duniya mu duba yanayin da ya fi dacewa, lokacin da adadin bayanai ya fi girman cache girma. Domin gwajin ya wuce cikin lokaci mai ma'ana (lokacin cache "dumi" yana ƙaruwa sosai yayin da girman ƙarar ya ƙaru), za mu iyakance girman girman zuwa 120GB.
Gwaji 3. Kwaikwayi Database
SSD cache
- Nau'in I/O: Database
- Girman Toshe Cache: 1MB
- Ƙofar Jama'a-kan-karanta: 2
- Ƙaddamarwa-kan-rubutu: 1
Tsarin I/O
- Kayan aiki: IOmeter V1.1.0
- Ma'aikata: 1
- Fitaccen (Zururin Queue): 128
- Ƙididdiga masu zuwa: 8KB, 67% Karanta, 100% Random
Tabbatarwa
Ƙarshe a bayyane, ba shakka, shine ingantaccen ingantaccen amfani da cache na SSD don inganta aikin kowane tsarin ajiya. Aiwatar zuwa Wannan bayanin yana aiki cikakke: ana aiwatar da aikin caching SSD daidai. Wannan ya shafi tallafi don karantawa da karantawa + yanayin rubutu, saitunan sassauƙa don kowane yanayin amfani, da kuma aikin gabaɗayan tsarin gaba ɗaya. Don haka, don farashi mai ma'ana (farashin lasisi yana kama da farashin 1-2 SSDs), zaku iya haɓaka aikin gabaɗaya sosai.
source: www.habr.com