raidz A variation on RAID-5 that allows for better dis- raidz1 tribution of parity and eliminates the "RAID-5 raidz2 write hole" (in which data 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, meaning 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.
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man zpool
raidz A variation on RAID-5 that allows for better dis-
raidz1 tribution of parity and eliminates the "RAID-5
raidz2 write hole" (in which data 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, meaning 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.
回复 4# wanbw
我就知道raid 5实际可用是n-2，一个校验，一个热备
N-1
双奇偶校验 和 单奇偶校验又能差多少呢