> 2011/5/26 Eugen Leitl <eu...@leitl.org>: > > How bad would raidz2 do on mostly sequential writes > and reads > > (Athlon64 single-core, 4 GByte RAM, FreeBSD 8.2)? > > > > The best way is to go is striping mirrored pools, > right? > > I'm worried about losing the two "wrong" drives out > of 8. > > These are all 7200.11 Seagates, refurbished. I'd > scrub > > once a week, that'd probably suck on raidz2, too? > > > > Thanks. > > Sequential? Let's suppose no spares. > > 4 mirrors of 2 = sustained bandwidth of 4 disks > raidz2 with 8 disks = sustained bandwidth of 6 disks > > So :)
Turn it around and discuss writes. Reads may or may not give 8x throughput with mirrors. In either setup, writes will require 8x storage bandwidth since all drives will be written to. Mirrors will deliver 4x throughput and RAIDZ2 will deliver 6x throughput. For what it's worth, I ran a 22 disk home array as a single RAIDZ3 vdev (19+3)for several months and it was fine. These days I run a 32 disk array laid out as four vdevs, each an 8 disk RAIDZ2, i.e. 4x 6+2. The best advice is simply to test your workload against different configurations. ZFS lets you pick what works for you. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
