Date: Sat, 23 May 2009 06:04:04 -0700 From: Randy Bush <randy@psg.com> To: Artis Caune <artis.caune@gmail.com> Cc: freebsd-fs <freebsd-fs@freebsd.org> Subject: Re: raidz2 a bit big Message-ID: <m27i08km2j.wl%randy@psg.com> In-Reply-To: <9e20d71e0905230537ibcaf852g1dc32b6ffc3a681d@mail.gmail.com> References: <m28wkon90c.wl%randy@psg.com> <9e20d71e0905230537ibcaf852g1dc32b6ffc3a681d@mail.gmail.com>
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>> 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. how are writes? > 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 ok. sounds nice. but then, don't i have six file systems and have to start playing lay-out design games? randy
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