Date: Tue, 19 Oct 2004 15:52:25 -0500 From: Mike Horwath <drechsau@geeks.org> To: =?iso-8859-1?B?Sm/jb19DYXJsb3NfTWVuZGVzX0x17XM=?= <jonny@jonny.eng.br> Cc: freebsd-performance@freebsd.org Subject: Re: Disk I/O Performance Message-ID: <20041019205225.GB39270@octanews.net> In-Reply-To: <41756EBF.3010008@jonny.eng.br> References: <20041019193501.GC78974@cybernetik.net> <41756EBF.3010008@jonny.eng.br>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, Oct 19, 2004 at 04:45:03PM -0300, João_Carlos_Mendes_Luís wrote: > I'd say that you have to check which CCD chunk size is best for > your needs. The manual for vinum recommends avoiding chunk sized to a > power of two, which is probably the first big mistake of everybody. > > Try mounting with option noatime, if you haven't already. And use > the largest block size possible when formatting. Last time I read about > there was a limit of 16384, but I would expect better performance for > large file with 64k blocks (and 8k frags). > > If you don't have a need for safety on the files, you could try > mount async and measure if it suits better you need for performance than > softupdates. Sometimes softupdates is faster, and it is always safer. All good ideas except the issue is bandwidth performance across the disks. I am seeing the same thing (and Kristofer and I have been working together, kinda, on this). It is as if I/O is being preferred for writing vs reading, very weird. His 5 disk stripe (well, it used to be five when I managed the machine) should not have issues, but this recently begun happening both on his systems and some of mine. Very odd stuff... -- Mike Horwath, reachable via drechsau@Geeks.ORG
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20041019205225.GB39270>