Date: Mon, 25 Feb 2013 16:15:13 +0100 From: Olivier Smedts <olivier@gid0.org> To: Kevin Day <toasty@dragondata.com> Cc: FreeBSD Filesystems <freebsd-fs@freebsd.org>, Scott Long <scottl@samsco.org>, wblock@freebsd.org Subject: Re: RFC: Suggesting ZFS "best practices" in FreeBSD Message-ID: <CABzXLYPn_TQ7etStsLCpmfW8Hv8jSX6Ab0j7Qap0wjrE8e2T5A@mail.gmail.com> In-Reply-To: <A196DCF7-B5C0-4EAB-960F-795D99A4B7F5@dragondata.com> References: <314B600D-E8E6-4300-B60F-33D5FA5A39CF@sarenet.es> <alpine.BSF.2.00.1301220804530.61512@wonkity.com> <A196DCF7-B5C0-4EAB-960F-795D99A4B7F5@dragondata.com>
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Hi, 2013/1/22 Kevin Day <toasty@dragondata.com>: > I run ftpmirror.your.org, which is a 72 x 3TB drive ZFS server. It's a ve= ry busy server. It currently houses the only off-site backup of all of the = Wikimedia projects(121TB), a full FreeBSD FTP mirror(1T), a full CentOS mir= ror, all of FreeBSD-Archive(1.5TB), FreeBSD-CVS, etc. It's usually running= between 100 and 1500mbps of ethernet traffic in/out of it. There are usual= ly around 15 FTP connections, 20-50 HTTP connections, 10 rsync connections = and 1 or 2 CVS connections. > > The only changes we've made that are ZFS specific are atime=3Doff and syn= c=3Ddisabled. Nothing we do uses atimes so disabling that cuts down on a to= n of unnecessary writes. Disabling sync is okay here too - we're just mirro= ring stuff that's available elsewhere, so there's no threat of data loss. O= ther than some TCP tuning in sysctl.conf, this is running a totally stock k= ernel with no special settings. If your workload is mostly made of reads (you're a mirror after all, you should only write when you're syncing with upstream servers) why use sync=3Ddisabled ? It shouldn't make a big difference for such a workload. > I've looked at using an SSD for meta-data only caching, but it appears th= at we've got far more than 256GB of metadata here that's being accessed reg= ularly (nearly every file is being stat'ed when rsync runs) so I'm guessing= it's not going to be incredibly effective unless I buy a seriously large S= SD. > > If you have any specific questions I'm happy to answer though. > > -- Kevin > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" --=20 Olivier Smedts _ ASCII ribbon campaign ( ) e-mail: olivier@gid0.org - against HTML email & vCards X www: http://www.gid0.org - against proprietary attachments / \ "Il y a seulement 10 sortes de gens dans le monde : ceux qui comprennent le binaire, et ceux qui ne le comprennent pas."
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