Date: Wed, 24 Nov 2004 12:32:23 +0100 From: Ivan Voras <ivoras@fer.hr> To: current@freebsd.org Subject: Re: gvinum panic? Message-ID: <41A47147.7040403@fer.hr> In-Reply-To: <20041124103613.GL7232@darkness.comp.waw.pl> References: <41A2488F.8030802@fer.hr> <20041122215228.J568@korben.in.tern> <41A33907.5020703@fer.hr> <20041124103613.GL7232@darkness.comp.waw.pl>
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Pawel Jakub Dawidek wrote: > +> linear read (1024 MB file, blocks of 32768) ................. 38.5 MB/s > +> linear write (1024 MB file, blocks of 32768) ................ 16.8 MB/s > +> random read (1024 MB file, blocks of 32768) ................. 41.9 MB/s > +> random write (1024 MB file, blocks of 32768) ................ 3.4 MB/s > In the interests of archives, I must say that the "random read" score above is WRONG. I was surprised myself because it's RAID3, so I rerun the test. Here are the correct numbers: linear read (2048 MB file, blocks of 32768) ................. 40.3 MB/s linear write (2048 MB file, blocks of 32768) ................ 16.8 MB/s random read (2048 MB file, blocks of 32768) ................. 5.1 MB/s random write (2048 MB file, blocks of 32768) ................ 2.9 MB/s (previously, most of the file has fitted into cache) > Do you use parity component for reading? If no, you can try it (add '-r' > option while configuring your raid3 device), it should speed up random > reads a lot. My situation is that there are 3 discs on 2 IDE channels, so two are in master-slave relationship. I've put the parity drive on the slave disc, and without -r it doesn't ever get touched (which speeds up the requests) The tests confirm this was right: (with round-robin/parity reads:) linear read (2048 MB file, blocks of 32768) ................. 32.6 MB/s linear write (2048 MB file, blocks of 32768) ................ 16.8 MB/s random read (2048 MB file, blocks of 32768) ................. 4.0 MB/s random write (2048 MB file, blocks of 32768) ................ 3.1 MB/s
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