From owner-freebsd-fs@FreeBSD.ORG Mon Feb 25 15:15:15 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 5B60D1F6 for ; Mon, 25 Feb 2013 15:15:15 +0000 (UTC) (envelope-from olivier@gid0.org) Received: from mail-ee0-f54.google.com (mail-ee0-f54.google.com [74.125.83.54]) by mx1.freebsd.org (Postfix) with ESMTP id ECAA2287 for ; Mon, 25 Feb 2013 15:15:14 +0000 (UTC) Received: by mail-ee0-f54.google.com with SMTP id c41so1469516eek.13 for ; Mon, 25 Feb 2013 07:15:13 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type:content-transfer-encoding :x-gm-message-state; bh=axMB73Iym45D+8oJaODrh1sE9cKF1PuBN96Hi3mrEpA=; b=na1GewtnAFYeDAXW7phuCGGKhhodoikuBzgahFWrDmB3gon6yYgZh9W82w0FwX/4y1 jCBNBDDbNtWXH7yoH0dROQsseS7U2jgiM0GvsBlEUM+1ZedaAfTPsjlWs3jgP1NhEd0T ri5XOr7hrajWNmd5Da10WG/Bwhi4pARmZNljipdlSWQcZy8Le9sgrjLvWyT5uO6GSQZa WyhL7sVmNpQwSOzFIcoM4FGk68jse4CQu24USQ+wCWP3YicyyWiQoUMGO/8W8vgAN0NX T8BmsPaKYDyBYgkLOhzGSEuDU/sZ1OKHhBBIf1jTZ649O5pqvKMN+FKZTXKjTUufW7AL WgfQ== MIME-Version: 1.0 X-Received: by 10.14.219.129 with SMTP id m1mr39716245eep.16.1361805313804; Mon, 25 Feb 2013 07:15:13 -0800 (PST) Received: by 10.14.179.65 with HTTP; Mon, 25 Feb 2013 07:15:13 -0800 (PST) In-Reply-To: References: <314B600D-E8E6-4300-B60F-33D5FA5A39CF@sarenet.es> Date: Mon, 25 Feb 2013 16:15:13 +0100 Message-ID: Subject: Re: RFC: Suggesting ZFS "best practices" in FreeBSD From: Olivier Smedts To: Kevin Day Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Gm-Message-State: ALoCoQlaNU+QTv0D9Je4dsQAw4v739eiKs64TXM4Pv6g9NdnB+UwByAmC8GhLCPmm/7Asy9HWF7Y Cc: FreeBSD Filesystems , Scott Long , wblock@freebsd.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Feb 2013 15:15:15 -0000 Hi, 2013/1/22 Kevin Day : > 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."