Date: Thu, 29 Mar 2012 09:46:16 -0500 (CDT) From: Bob Friesenhahn <bfriesen@simple.dallas.tx.us> To: Franz Schober <franz.schober@firmos.at> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS Performance FreeBSD 9.0 vs. Openindiana Message-ID: <alpine.GSO.2.01.1203290939590.1678@freddy.simplesystems.org> In-Reply-To: <4F74220E.9070707@firmos.at> References: <4F74220E.9070707@firmos.at>
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On Thu, 29 Mar 2012, Franz Schober wrote: > > For performance tests, I use the iozone benchmark with a multi-streaming > concurrency test, > iozone -o -c -t 8 -r 128k -s 4G (Sync Mode, 8 concurrent workers, 128 k > Recordsize, 4G working file for every worker to run not only in cache). The 128k record size is special. I think that this is the transition point where zfs writes sync data directly to the pool disks rather than to the log disks. I don't know which way it goes (pool/log) at exactly 128k. If your log disks are idle during the benchmark, then the answer to this question would be clear. > Now my question: Which parameters in the ZFS Subsystem of FreeBSD are > tuneable to reach the same performance in FreeBSD, > especially pushing the synchronous write performance ? I do not see much difference with the writes. I do see a large difference with the reads. This could easily be due to a difference in how Solaris and FreeBSD manage kernel memory. In Solaris, substantial caching may still be taking place even though you tried to avoid it. The ARC size might be too small (by default) under FreeBSD to offer similar caching. Bob -- Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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