Date: Fri, 15 Aug 1997 11:56:00 +0200 (MET DST) From: Paul Dekkers <psd@worldaccess.nl> To: Wes Peters <softweyr@xmission.com> Cc: questions@freebsd.org Subject: Re: FreeBSD is slower than Linux !? Message-ID: <Pine.LNX.3.96.970815115245.529A-100000@gromit.nev.ml.org> In-Reply-To: <199708150543.XAA16622@obie.softweyr.ml.org>
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On Thu, 14 Aug 1997, Wes Peters wrote: >Paul Dekkers writes: > > But, my main question -> I think FreeBSD is that slow because it writes > > everything to disk directly, without a good cache. Why is this like it is? > > This does not make FreeBSD very attractive for me to use as a fileserver > > (nfs or samba) or e.g. a mail server. > >To malign one of Mr. Clemens more famous quotes: >There are three kinds of lies: lies, damned lies, and benchmarks. > >That would depend on whether you want your files fast, or want them to >still exist when the power goes out. On Linux, the default is mount >drives asynchronously, on the BSD the default is synchronous. To quote >from the FreeBSD mount(8) man page: Even with async mode on it's still slow... Look at what a AIX does: Haven't seen anything faster than that, and I think it uses synced disks... And, by the way, when using an asynced disk, it isn't absolutely unsafe, am I right? When running sync once a day it writes everything to disk or not ?! (maybe mount /var with sync, en /www (or smth) with async ...) nic% time 0.080u 0.070s 0:06.48 2.3% 176+96k 0+0io 0pf+0w nic% time dd if=/dev/zero of=test bs=1024 count=5000 5000+0 records in 5000+0 records out 0.010u 1.010s 0:01.83 55.7% 0+0k 0+0io 13pf+0w nic% time sync 0.010u 0.320s 0:01.97 16.7% 11+0k 0+0io 8pf+0w >The options are there, and the choice is yours. For a web server that >gets a *lot* of hits, or a news server, you may want to use async. Do >really good backups on your web files. For a mail server, if you >consider your mail important, I wouldn't think of it. For a development >system or other volatile but somewhat non-critical, async might be a >possibility. I certainly wouldn't use it on *my* central source code >repository. I'm not sure if it's that unsafe; running sync writes everything to disk, so after updating your websites just run sync and I'll be happy :-) -= Paul =-
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