RAID 5
Random Read Performance: Very good to excellent; generally better for larger stripe sizes. Can be better than RAID 0 since the data is distributed over one additional drive, and the parity information is not required during normal reads.
Random Write Performance: Only fair, due to parity overhead; this is improved over RAID 3 and RAID 4 due to eliminating the dedicated parity drive, but the overhead is still substantial.
Sequential Read Performance: Good to very good; generally better for smaller stripe sizes.
Sequential Write Performance: Fair to good.
Ak sa to porovna s RAID 1+0 tak:
Random Read Performance: Very good to excellent.
Random Write Performance: Good to very good.
Sequential Read Performance: Very good to excellent.
Sequential Write Performance: Good to very good.
RAID 5 nie je dobre riesenie, ak sa nechce prist o data. Staci jeden zle zapisany bit a parita pokasle dalsie data. A staci ze odidu dva disky a 100% dat je v prdeli. Mozno si teraz neiekto pomysli, ze naraz 2 disky odist nemozu - tak nech si spomenie na december roku 2001 tusim, kedy sa toto stalo serveru host.sk :) Cize namiesto draheho radica staci kupit jeden disk, pretoze ina uspora RAID 5 oproti RAID 1+0 nie je. Pole ma lepsie vlastnosti a mozu odist hned dva disky naraz a nic sa nedeje. Softwareovy RAID 5 je onicom, kedze vypocty parity pri I/O operaciach musi robit procesor. Ja preto RAID 5 silne neodporucam