5 ms·
If you're using RAID-Z on zfs, your comparison isn't fair. Rather than use RAID56 with btrfs, the equivalent would be to get 1 or 2 disk redundancy with raid1 o
by accelbred 6y ago
If you're using RAID-Z on zfs, your comparison isn't fair. Rather than use RAID56 with btrfs, the equivalent would be to get 1 or 2 disk redundancy with raid1 or raid1c3.
- trasz 6y agoNot really - RAIDZ is basically RAID5 without the write hole problem. ZFS equivalent to RAID1 is called 'mirror', and is... well, a mirror.
- accelbred 6y agoYes, and btrfs's raid1 isn't a mirror. Btrfs's raid1c3 and raid1c4 are its alternative to raid5/6 without the write hole.
- deleted 6y ago[deleted]
- trasz 6y agoNo, it's still a mirror, just spread over more than two devices. Size overhead is still that of a mirror, ie quite a bit higher than that of raidz.
- tw04 6y agoRAID-Z is the equivalent of RAID-5. RAID-Z2 is the equivalent of RAID-6. RAID-Z3 would be the equivalent of RAID-7 (or whatever the standard is named for 3-disk parity). This is strictly speaking to how it deals with data and parity, the implementations are obviously different. RAID-1 would be a mirror in ZFS parlance.
- accelbred 6y agoBTRFS raid1 isn't mirroring drives though, it means there are two copies of each extent across the whole set of 2+ drives. and BTRFS and raid1c3 and raid1c4 are 3 and 4 copies.