[FUG-BR] Raid 5 (ZFS)

[Márcio Luciano Donada]

Em 5/5/2010 01:27, Nenhum_de_Nos escreveu:
>
> Renato,
>
> salvo engano, raidz no zfs num faz o mesmo que Raid5 ? (seria somente um apelido do zfs) (naõ achei página falando agora, num procurei tanto tb :)
>
>   


Da man page do zpool

raidz         A  variation on RAID-5 that allows for better distribution of
raidz1       parity and eliminates the "RAID-5 write hole" (in which  data
raidz2       and  parity become inconsistent after a power loss). Data and
                 parity is striped across all disks within a raidz group.

                 A raidz group can have either single- or double-parity,
mean-
                 ing  that  the  raidz  group  can sustain one or two
failures
                 respectively without losing any data. The  raidz1 
vdev  type
                 specifies  a  single-parity  raidz  group and the
raidz2 vdev
                 type specifies a double-parity raidz group.  The 
raidz  vdev
                 type is an alias for raidz1.

                 A  raidz group with N disks of size X with P parity
disks can
                 hold  approximately  (N-P)*X  bytes  and  can  
withstand   P
                 device(s)  failing  before data integrity is
compromised. The
                 minimum number of devices in a raidz group is one 
more  than
                 the number of parity disks. The recommended number is
between
                 3 and 9 to help increase performance.