Date: Thu, 09 Nov 2006 01:13:54 +0000 From: Pete French <petefrench@ticketswitch.com> To: freebsd-stable@FreeBSD.ORG Subject: Dissapointing performance of ciss RAID 0+1 ? Message-ID: <E1GhyUM-000Oct-6G@dilbert.firstcallgroup.co.uk>
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I recently overhauled my RAID array - I now have 4 drives arranged as RAID 0+1, all being 15K 147gig Fujitsu's, and split across two buses, which are actively terminated to give U160 speeds (and I have verified this). The card is a 5304 (128M cache) in a PCI-X slot. This replaces a set of 6 7200 rpm drives as RAID 5 which were running at 40meg speeds due to non LVD termination. I would expect to see a large speed increase wouldn't I ? But it remains about the same - around 45 meg/sec for reading a large file (3 gig or so) and half that for copying said file. These are 'real world' tests in the sense that I us the drive for building large ISo images and copying them around - I really dont care what benchmarks say, it's the speed of these two operatiosn that I want to make fats. I've tried all the possible stripe sizes (128k gives the best performance) but still I only get the above speeds. Just one of the 15k drives on it's own performs better than this! I would expect the RAID-0 to give me at least some speedup, or in the worst case be the same, surely ? Booting up Windowws and running some tests gives me far better performance however, so I am wondering if there is some driver issue here. Has anyone else seen the same kind of results ? I am running the latest stable for amd64 and the machine has twin opteron 242's with a gig of RAM each. surely it can do better than this ? -pcf.
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