Date: Mon, 6 Nov 2006 21:12:34 +0200 From: Oles Hnatkevych <don_oles@able.com.ua> To: Oliver Fromme <freebsd-geom@freebsd.org> Cc: freebsd-perfomance@freebsd.org, pjd@freebsd.org Subject: Re[2]: geom stripe perfomance question Message-ID: <512766008.20061106211234@able.com.ua> In-Reply-To: <200611061204.kA6C4FXt079703@lurza.secnetix.de> References: <961295086.20061105000919@able.com.ua> <200611061204.kA6C4FXt079703@lurza.secnetix.de>
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Hello, All It turns out that it was a hardware/controller problem. The benchmarks with 'dd bs=1m' gave the following results. Two disks Samsung SP2514N, stripe size 65kb The controller ICH2 (ATA100), Celeron 800: ad(x): ~72 Mb/sec ad1 & ad2 in parallel: ~33 Mb/sec each (disks on separate ATA channels) stripe: ~65-68 Mb/sec The controller VIA 82xxxx (ATA133), Athlon 1700+ ad(x): 72-74 Mb/sec ad1 & ad2 in parallel (same ATA channel): ~26Mb/sec each! ad1 & ad2 in parallel (different ATA channels): same as one disk! stripe (different ATA channels): ~144 Mb/sec (even without kern.geom.stripe.fast option). What really is surprising that disks on the same ATA channel on VIA controller behave much worse than half of their full speed. Yet on a different ATA channels they perform flawlessly. Seems like the gmirror(8) man page should contain a separate paragraph telling about peculiarities using old ATA controllers or using disks on the same ATA channel. ;-) -- Oles Hnatkevych mailto:don_oles@able.com.ua
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