Date: Fri, 28 Jan 2005 09:52:38 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Mike Tancsa <mike@sentex.net> Cc: freebsd-questions@FreeBSD.org Subject: Re: FreeBSD 5.3 I/O Performance / Linux 2.6.10 | Continued Discussion Message-ID: <Pine.NEB.3.96L.1050128095110.68140C-100000@fledge.watson.org> In-Reply-To: <6.2.0.14.0.20050127213817.02f19220@64.7.153.2>
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On Thu, 27 Jan 2005, Mike Tancsa wrote: > >I/O (reads, writes at fairly large multiples of the sector size -- 512k is > >a good number) and small I/O size (512 bytes is good). This will help > >identify the source along two dimmensions: are we looking at a basic > >storage I/O problem that's present even without the file system, or can we > >conclude that some of the additional extra cost is in the file system code > >or the hand off to it. Also, with the large and small I/O size, we can > >perhaps draw some conclusions about to what extent the source is a > >per-transaction overhead. > > Apart from postmark and iozone (directly to disk and over nfs), are > there any particular tests you would like to see done ? Just to get started, using dd to read and write at various block sizes is probably a decent start. Take a few samples, make sure there's a decent sample size, etc, and don't count the first couple of runs. Robert N M Watson
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