Date: Sat, 23 May 2009 15:37:14 +0300 From: Artis Caune <artis.caune@gmail.com> To: Randy Bush <randy@psg.com> Cc: freebsd-fs <freebsd-fs@freebsd.org> Subject: Re: raidz2 a bit big Message-ID: <9e20d71e0905230537ibcaf852g1dc32b6ffc3a681d@mail.gmail.com> In-Reply-To: <m28wkon90c.wl%randy@psg.com> References: <m28wkon90c.wl%randy@psg.com>
next in thread | previous in thread | raw e-mail | index | archive | help
2009/5/23 Randy Bush <randy@psg.com>:
> a dozen 2tb drives in a raidz2
>
> dfw1.psg.com:/root# zpool status
> pool: tank
> state: ONLINE
> scrub: none requested
> config:
>
> NAME STATE READ WRITE CKSUM
> tank ONLINE 0 0 0
> raidz2 ONLINE 0 0 0
> da0s3 ONLINE 0 0 0
> da1s3 ONLINE 0 0 0
> da2s1 ONLINE 0 0 0
> da3s1 ONLINE 0 0 0
> da4s1 ONLINE 0 0 0
> da5s1 ONLINE 0 0 0
> da6s1 ONLINE 0 0 0
> da7s1 ONLINE 0 0 0
> da8s1 ONLINE 0 0 0
> da9s1 ONLINE 0 0 0
> da10s1 ONLINE 0 0 0
> da11s1 ONLINE 0 0 0
Reads on such configurations are very slow.
If one of your disk, for example, is capable of 100 IO per/sec, then:
with 12 disks in one raidz2 vdev you get only 100 IOPS
with 4 disks in raidz2 (total 3 raidz2 vdevs) you get 300 IOPS
with 2 disks in mirror (total 6 mirror vdevs) you can get 1200 IOPS
--
Artis Caune
Everything should be made as simple as possible, but not simpler.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9e20d71e0905230537ibcaf852g1dc32b6ffc3a681d>