Kuti kernel ikwanise kushanda Linux 6.2 inopa mazano ekuvandudza maBtrfs kuti agadzirise dambudziko re "write hole" muRAID 5/6 implementations. Dambudziko iri rinobva pakuti kana paine kutadza kunyora panguva yekunyora, pakutanga hazvigoneke kuona kuti ndeipi block yakanyorwa nemazvo pamudziyo weRAID uye ndeipi isina. Kana kuyedza kudzoreredza RAID kukaedzwa mumamiriro ezvinhu aya, mablock anoenderana nemablock asina kunyorwa anogona kukanganiswa, sezvo mamiriro eRAID block asina kuenderana. Dambudziko iri rinoitika mune chero RAID 1/5/6 arrays isingashandise matanho akakosha ekuderedza dambudziko iri.
Mukushandiswa kweRAID seRAID1 mu btrfs, dambudziko iri rinogadziriswa nekushandisa cheki pamakopi ese ari maviri; kana pane mutsauko, iyo data inongodzoreredzwa kubva kune yechipiri kopi. Iyi nzira inoshandawo kana mudziyo ukatanga kudzorera data isiriyo pane kutadza zvachose.
Nekudaro, muRAID5/6, iyo faira system haina kuchengetedza macheki ezvivharo zvepari: kazhinji, kurongeka kwezvivharo kunosimbiswa nekuti ivo vese vane cheki, uye iyo parity block inogona kuvakwazve kubva kune data. Zvisinei, munyaya yekunyora zvishoma, nzira iyi inogona kukundikana mune mamwe mamiriro ezvinhu. Muchiitiko ichi, pakudzorera hurongwa, zvinokwanisika kuti zvivharo zvakakanganiswa nekunyora kusina kukwana zvichavakwa zvakare zvisizvo.
Panyaya ye btrfs, dambudziko iri rinonyanya kuoma kana kunyora kuri kuitwa kuri kudiki pane mutsetse. Muchiitiko ichi, iyo faira system inofanira kuita kuverenga-shandura-nyora (RMW) kushanda. Kana oparesheni iyi ikasangana nemabhuroki asina kukwana kunyora, mashandiro eRMW anogona kukonzera huwori hunozoenda husingaonekwe, zvisinei nemacheki. Vagadziri vacho vakaita shanduko kuitira kuti RMW ishande inoongorora block checksum isati yaita oparesheni uye, kana kudzoreredzwa kwedata kuchidikanwa, inoongororawo macheki mushure mekunyora. Nehurombo, kana iri chikamu chemitsetse inonyora (RMW), izvi zvinotungamira kune imwe yepamusoro yekuverenga macheki, asi zvakanyanya kunatsiridza kuvimbika. Iyi pfungwa haisati yagadzirira RAID 6, asi nekuda kwekukundikana kwakadaro muRAID 6, kunyora kunofanira kukundikana pamidziyo miviri panguva imwe chete, iyo ishoma.
Pamusoro pezvo, mazano evagadziri ekushandisa RAID5/6 akakosha. Mhedziso yeiyi kurudziro ndeyekuti muBtrfs, iyo metadata uye data rekuchengetedza profiles zvinogona kusiyana. Muchiitiko ichi, unogona kushandisa RAID1 (girazi) kana kunyange RAID1C3 (makopi matatu) purogiramu yemetadata, uye RAID5 kana RAID6 yedata. Izvi zvinova nechokwadi chekuchengetedzwa kwemetadata uye kusavapo kwemaburi ekunyora, ukuwo ichipa kushandiswa kwakanyatsoita kwenzvimbo yakajairika yeRAID5/6. Izvi zvinodzivirira huwori hwemetadata, uye huwori hwe data hunogona kugadziriswa.
Izvo zvakakoshawo kuziva kuti asynchronous "kurasa" mashandiro (kumaka mabhuroki akasunungurwa asingachagone kuchengetwa mumuviri) anozogoneswa nekusarudzika kune SSD muBtrfs mukernel 6.2. Kubatsira kweiyi modhi kuita kwepamusoro nekuda kwekunyatso kurongeka kwe "kurasa" mashandiro mumutsara uye kunotevera kugadziriswa kwemutsetse nemunhu anobata kumashure. Izvi zvinoreva kuti zvakajairwa faira system mashandiro haana kudzikiswa sezvo mabhuraki anosunungurwa, sezvazvakaita ne "kurasa" inowirirana, uye SSD inogona kuita zvirinani sarudzo. Nekune rimwe divi, hapasisina kudikanwa kwekushandisa zvinoshandiswa senge fstrim, sezvo ese mabhururu aripo achacheneswa muhurongwa hwefaira pasina kudiwa kwekuwedzera scanning kana kudzikisira mashandiro.
Source: opennet.ru
