RAID thiab Mass Storage

RAID tswvyim

Lub hom phiaj tseem ceeb ntawm RAID yog los muab cov peev txheej khaws cia siab kawg thiab cov ntaub ntawv tsis txaus ntseeg rau cov servers loj. Nyob rau hauv ib qho system, RAID yog pom raws li ib tug logical muab faib, tab sis nws yog tsim los ntawm ntau hard disks (tsawg kawg yog ob). Nws txhim kho cov ntaub ntawv dhau los ntawm kev khaws cia los ntawm ib txhij khaws thiab khaws cov ntaub ntawv hla ntau lub disks. Ntau RAID configurations muaj kev ntsuas rau kev sib nrig sib txheeb xyuas / rov qab, nrog rau ncaj qha mirroring backup. Qhov no zoo heev txhim kho qhov ua txhaum cai ntawm RAID systems thiab txhim kho qhov system stability thiab redundancy, li no lo lus "Redundant."

RAID siv los ua ib qho khoom tshwj xeeb hauv SCSI sau, txwv los ntawm nws cov thev naus laus zis thiab tus nqi, uas cuam tshuam nws txoj kev loj hlob hauv kev lag luam qis. Niaj hnub no, nrog rau kev loj hlob ntawm RAID thev naus laus zis thiab kev siv zog tas li los ntawm cov tuam txhab, cov kws tsim khoom khaws cia tuaj yeem txaus siab rau cov nqi siv nyiaj ntau dua IDE-RAID. Txawm hais tias IDE-RAID yuav tsis phim SCSI-RAID raws li kev ruaj ntseg thiab kev ntseeg siab, nws qhov kev ua tau zoo ntawm ib qho nyuaj drives yog qhov txaus nyiam rau ntau tus neeg siv. Qhov tseeb, rau kev ua haujlwm qis qis txhua hnub, IDE-RAID yog ntau tshaj qhov muaj peev xwm.

Zoo ib yam li modems, RAID tuaj yeem raug cais raws li software-based, semi-software / semi-hardware, lossis tag nrho cov khoom siv kho vajtse. Tag nrho software RAID hais txog RAID qhov twg txhua qhov kev ua haujlwm tau ua haujlwm los ntawm kev ua haujlwm (OS) thiab CPU, tsis muaj kev tswj hwm thib peb / kev ua haujlwm (feem ntau hu ua RAID co-processor) lossis I / O nti. Hauv qhov no, txhua txoj haujlwm RAID ntsig txog yog ua los ntawm CPU, uas ua rau muaj kev ua haujlwm qis tshaj ntawm RAID hom. Semi-software / semi-hardware RAID feem ntau tsis muaj nws tus kheej I / O ua chip, yog li CPU thiab cov kev pab cuam tsav tsheb yog lub luag haujlwm rau cov haujlwm no. Tsis tas li ntawd, RAID tswj / ua cov chips siv hauv semi-software / semi-hardware RAID feem ntau muaj peev xwm txwv thiab tsis tuaj yeem txhawb nqa qib RAID siab. Tag nrho cov khoom siv RAID suav nrog nws tus kheej RAID tswj / ua haujlwm thiab I / O ua cov chips, thiab txawm tias suav nrog array tsis (Array Buffer). Nws muaj qhov zoo tshaj plaws tag nrho kev ua tau zoo thiab kev siv CPU ntawm peb hom, tab sis kuj los nrog cov khoom siv siab tshaj plaws. Thaum Ntxov IDE RAID phaib thiab motherboards siv HighPoint HPT 368, 370, thiab PROMISE chips tau txiav txim siab ib nrab software / semi-hardware RAID, vim lawv tsis muaj cov txheej txheem I / O ua haujlwm siab. Ntxiv mus, RAID tswj / ua cov chips los ntawm ob lub tuam txhab no muaj peev xwm txwv thiab tsis tuaj yeem ua haujlwm ua haujlwm nyuaj, yog li tsis txhawb RAID qib 5. Ib qho piv txwv tseem ceeb ntawm tag nrho cov khoom siv RAID yog AAA-UDMA RAID daim npav ua los ntawm Adaptec. Nws nta lub siab ua haujlwm siab RAID co-processor thiab Intel 960 tshwj xeeb I / O processor, txhawb nqa RAID qib 5. Nws sawv cev rau cov khoom lag luam IDE-RAID siab tshaj tam sim no. Table 1 piv cov software RAID thiab kho vajtse RAID hauv kev lag luam kev siv.