On Tue, 28 Apr 2015 14:31:23 -0400, Rich Freeman wrote: > >> btrfs raid5 is still fairly experimental (though now it supports > >> recovery) and works more-or-less how you'd expect raid5 to work. > >> Raid1 on btrfs gives you the capacity of n/2 and not n-1 disks, > > > > You're right, I was clearly confused (an oxymoron?) when I wrote that. > > > > So RAID1 gives less capacity than RAID5 on BTRFS, but it is stable (in > > btrfs terms). > > > > For drives of identical size and not using compression, I'd expect > space use on btrfs to be equivalent to the same raid level on > mdadm+lvm+ext4.
That's only true for RAID1 when you have 2 drives, with more drives btrfs
gives more space.
3 x 2TB drives give 2TB on MD RAID1
3 x 2TB drives give 3TB on btrfs RAID1
Although you will get slightly less usable space with btrfs because of
the space used for metadata, but I'm not sure how significant that is.
--
Neil Bothwick
QOTD:
The only easy way to tell a hamster from a gerbil is that the
gerbil has more dark meat.
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