Date: Wed, 23 Dec 2009 19:18:41 -0800 From: Matt Simerson <matt@corp.spry.com> To: freebsd-fs@freebsd.org Subject: Re: ZFS RaidZ2 with 24 drives? Message-ID: <1555A977-DDDB-47A5-83AF-4096D610C73C@spry.com> In-Reply-To: <1696529130.20091223212612@pyro.de> References: <568624531.20091215163420@pyro.de> <42952D86-6B4D-49A3-8E4F-7A1A53A954C2@spry.com> <957649379.20091216005253@pyro.de> <26F8D203-A923-47D3-9935-BE4BC6DA09B7@corp.spry.com> <1696529130.20091223212612@pyro.de>
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On Dec 23, 2009, at 12:26 PM, Solon Lutz wrote: > Hi, >=20 > I opted for two 12-disc raidz2.=20 > Reasons were: Space is more important than performance. >=20 > But performance is very poor - have a look at the iostats - sometimes = nothing really seems > to happen for up to ten seconds, or very little data gets written. = Might this be a problem > of the amd64 system having only 4GB of RAM? Any tuneable sysctls? = Enabling prefetch didn't help...:=20 When testing on a i386 system with only 4GB of ram, disabling prefetch = did help. There are the settings I used, way back when... $ cat /boot/loader.conf=20 #vm.kmem_size=3D"1024M" #vm.kmem_size_max=3D"1024M" #vfs.zfs.prefetch_disable=3D1 #vfs.zfs.arc_min=3D"16M" #vfs.zfs.arc_max=3D"64M" I ultimately worked around that problem by no longer using raidz2. Matt > capacity operations bandwidth = capacity operations bandwidth > pool used avail read write read write pool = used avail read write read write > ---------- ----- ----- ----- ----- ----- ----- ---------- = ----- ----- ----- ----- ----- ----- > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 1.23K 0 153M > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 0 0 510 > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 0 0 510 > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 835 0 104M > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 645 0 68.7M > backup-7 1.23T 130G 0 0 0 0 store-1 = 616G 15.6T 0 0 0 0 > backup-7 1.23T 130G 474 0 59.3M 0 store-1 = 616G 15.6T 0 4 0 5.49K > backup-7 1.23T 130G 494 0 61.8M 0 store-1 = 616G 15.6T 0 0 0 0 > backup-7 1.23T 130G 53 0 6.73M 0 store-1 = 617G 15.6T 0 19 0 39.4K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 30 0 140K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 33 0 72.8K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 65 0 162K > backup-7 1.23T 130G 71 0 8.92M 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 636 0 79.4M 0 store-1 = 617G 15.6T 0 4 0 10.5K > backup-7 1.23T 130G 485 0 60.6M 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 85 0 10.7M 0 store-1 = 617G 15.6T 0 15 0 39.9K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 17 0 40.4K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 31 0 73.3K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 62 0 156K > backup-7 1.23T 130G 17 0 2.24M 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 189 0 23.6M 0 store-1 = 617G 15.6T 0 9 0 14.0K > backup-7 1.23T 130G 2 74 133K 247K store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 12 0 17.5K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 1 0 255K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 100 0 12.6M > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 1012 0 126M > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 33 0 137K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 19 0 293K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 153 0 19.2M > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 109 0 13.7M > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 4 0 15.5K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 1.54K 0 188M > backup-7 1.23T 130G 6 0 888K 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 556 0 69.5M 0 store-1 = 617G 15.6T 0 8 0 11.0K > backup-7 1.23T 130G 500 0 62.5M 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 5 0 766K 0 store-1 = 617G 15.6T 0 16 0 30.4K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 29 0 136K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 38 0 84.7K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 57 0 145K > backup-7 1.23T 130G 92 0 11.6M 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 497 0 62.1M 0 store-1 = 617G 15.6T 0 8 0 9.48K > backup-7 1.23T 130G 534 0 66.7M 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 153 0 19.2M 0 store-1 = 617G 15.6T 0 12 0 12.0K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 26 0 101K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 34 0 76.3K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 62 0 155K > backup-7 1.23T 130G 75 0 9.48M 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 690 0 86.3M 0 store-1 = 617G 15.6T 0 6 0 12.0K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 10 0 14.0K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 1 0 255K > backup-7 1.23T 130G 0 0 0 0 store-1 = 617G 15.6T 0 0 0 0 >=20 >=20 >=20 >=20 > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
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