Date: Thu, 09 Nov 2006 13:36:44 +0100 From: Ivan Voras <ivoras@fer.hr> To: Pete French <petefrench@ticketswitch.com> Cc: freebsd-stable@freebsd.org Subject: Re: Dissapointing performance of ciss RAID 0+1 ? Message-ID: <455320DC.40302@fer.hr> In-Reply-To: <E1Gi8ZC-000Dgf-QH@dilbert.firstcallgroup.co.uk> References: <E1Gi8ZC-000Dgf-QH@dilbert.firstcallgroup.co.uk>
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Pete French wrote: > reading from the filesystem with the vfs.read_max set to 64 I now get > 112 meg/second though ?!!! how can the filesystem give me better performance > than the raw device ? I do not think this is a caching issue as I am using > a test file nearly twice the size of the RAM in the system to get round this. > > I am delighted by the performance increase, but the results do not make sense. It would be interesting for you to track iostat (i.e. run "iostat 1") with and without modified vfs.read_max and see if there's a difference. In a similar experiment, you could watch gstat (also before and after) and see if it reports the difference.
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