Date: Mon, 5 Oct 1998 18:01:59 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: michaelh@cet.co.jp (Michael Hancock) Cc: eilts@tor.muc.de, freebsd-fs@FreeBSD.ORG Subject: Re: filesystem safety and SCSI disk write caching Message-ID: <199810051801.LAA21073@usr01.primenet.com> In-Reply-To: <Pine.BSF.3.95LJ1.1b3.981005104432.2489A-100000@sv01.cet.co.jp> from "Michael Hancock" at Oct 5, 98 10:48:11 am
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> > > I can post (once again) the results of a Novell study on server usage > > > patterns. The 30,000 foot view for a typical server breaks down to: > > > > > > 75% reads > > > 15% writes > > > 8% directory search operations > > > 2% other > > > > How does this translate to disk usage? I think, VM/buffer cache will > > reduce reads and directory search operations quite a lot. > > No. Yes. The ratio of actual disk writes to disk reads is probably enough > to justify the effort to optimize writes. According to other postings in this thread, the empirical difference in wall time measured on the prototypical FreeBSD benchmark of "make world" is 5.6% between async + noatime vs. soft updates. While it would be worthwhile to attempt to optimize this further, I think doing so by enabling write caching is a cop-out. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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