Prvo moraš da znaš šta hoćeš da dobiješ, a onda da vidiš šta ćeš da realizuješ...
RAID 0 -- Striped Disk Array without Fault Tolerance: Provides data striping (spreading out blocks of each file across multiple disk drives) but no redundancy. This improves performance but does not deliver fault tolerance. If one drive fails then all data in the array is lost.
RAID 1 -- Mirroring and Duplexing: Provides disk mirroring. Level 1 provides twice the read transaction rate of single disks and the same write transaction rate as single disks.
RAID 2 -- Error-Correcting Coding: Not a typical implementation and rarely used, Level 2 stripes data at the bit level rather than the block level.
RAID 3 -- Bit-Interleaved Parity: Provides byte-level striping with a dedicated parity disk. Level 3, which cannot service simultaneous multiple requests, also is rarely used.
RAID 4 -- Dedicated Parity Drive: A commonly used implementation of RAID, Level 4 provides block-level striping (like Level 0) with a parity disk. If a data disk fails, the parity data is used to create a replacement disk. A disadvantage to Level 4 is that the parity disk can create write bottlenecks.
RAID 5 -- Block Interleaved Distributed Parity: Provides data striping at the byte level and also stripe error correction information. This results in excellent performance and good fault tolerance. Level 5 is one of the most popular implementations of RAID.
RAID 6 -- Independent Data Disks with Double Parity: Provides block-level striping with parity data distributed across all disks.
RAID 0+1 – A Mirror of Stripes: Not one of the original RAID levels, two RAID 0 stripes are created, and a RAID 1 mirror is created over them. Used for both replicating and sharing data among disks.
RAID 10 – A Stripe of Mirrors: Not one of the original RAID levels, multiple RAID 1 mirrors are created, and a RAID 0 stripe is created over these.
RAID 7: A trademark of Storage Computer Corporation that adds caching to Levels 3 or 4.
RAID S: EMC Corporation's proprietary striped parity RAID system used in its Symmetrix storage systems.
Dakle, u odnosu na to šta želiš i koliko hardova imaš, tako ćeš si i izabrati konfiguraciju svog RAID sistema.
Ovdje bi trebalo napomenuti, ako se već ne zna, da su na pločama dostupnim krajnjim kupcima (velikoj većini nas) integrisani polu HW/polu SW RAID kontroleri. Pravi RAID kontroleri imaju samostalnu ECC keš memoriju i uopšte ne opterećuju CPU u svom radu (ako je 1-2% uopšte opterećenje). Moderni RAID kontroleri integrisani na našim običnim pločama su porastom snage CU-ova dosta napredovali po pitanju zauzeća (opterećenja) centralnog procesora u toku svoga rada, pa su i oni svoje opterećenje smanjili na skoro neprimjetnu mjeru.
Ipak, jedino RAID kontroler u vidu PCI(-X) kartice sa svojim procesorom, svojom RAM memorijom sa ECC i baterijom je pravi RAID kontroler.
I na kraju, da ne bude zabune, i ovi integrisani RAID kontroleri koje imamo na pločama mogu da ubrzaju svaku mašinu na kojoj se podigne RAID niz.
:wave:
PS: Hope it helps...
EDIT:
E, da. Još nešto. Postoji i jedan mod koji se zove JBOD (Just a Bunch of Ordinary Disks). Ovim modom se spajaju svi diskovi u jedan veliki disk (prosto zbrajanje kapaciteta), ali bez dobitka na performansama...