From owner-freebsd-fs@FreeBSD.ORG Fri Apr 5 14:59:41 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 04A7BE35 for ; Fri, 5 Apr 2013 14:59:41 +0000 (UTC) (envelope-from peter.maloney@brockmann-consult.de) Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.187]) by mx1.freebsd.org (Postfix) with ESMTP id 7F1DFB55 for ; Fri, 5 Apr 2013 14:59:40 +0000 (UTC) Received: from [10.3.0.26] ([141.4.215.32]) by mrelayeu.kundenserver.de (node=mreu2) with ESMTP (Nemesis) id 0LwVC7-1UgKgv3TAt-017kz2; Fri, 05 Apr 2013 16:59:38 +0200 Message-ID: <515EE6D9.8050605@brockmann-consult.de> Date: Fri, 05 Apr 2013 16:59:37 +0200 From: Peter Maloney User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Ronald Klop Subject: Re: Regarding regular zfs References: <8B0FFF01-B8CC-41C0-B0A2-58046EA4E998@my.gd> <515EB744.5000607@brockmann-consult.de> In-Reply-To: X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Provags-ID: V02:K0:DpPcoJf3XUZrn3D4ybLZgywMOVtj+xtLs/Rn2TIoDfW 1Y1KB4Slp+BNsO7MHahIMsBhefmqC+qfoJQIYnBoDseA15qCU+ 5twiEUkGjT9xo0DoXBda3E6rUA8eiL71vw9VobqFWwGZXSrE09 A+abL6PDbc29zqGKmgcqpojiFKUTt6QYnUiIYEwadlKriRMG4f uwybz7UKkefg93AXu7jOKGhUAJQstcJEP9UJfSY6nBVXHOr2qR 5LMbjkjTaOIJi2JxTXzGhk3TONxXp6gvxbMISYmJoR+JV9oCE7 ocuspQvzDIlmnGDBLDQqSpjttTdaO8FUWcmcCH9Wy4EONK3P5h Fa8TqjQGzq+dkt8ndJCa7d3WnAu5bMTUceYwbUZJO Cc: "freebsd-fs@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: Fri, 05 Apr 2013 14:59:41 -0000 On 2013-04-05 16:07, Ronald Klop wrote: > On Fri, 05 Apr 2013 15:02:12 +0200, Joar Jegleim > wrote: > >> You make some interesting points . >> I don't _think_ the script 'causes more than 1 zfs write at a time, >> and I'm >> sure 'nothing else' is doing that neither . But I'm gonna check that out >> because it does sound like a logical explanation. >> I'm wondering if the rsync from the receiving server (that is: the >> backup >> server is doing rsync from the zfs receive server) could 'cause the same >> problem, it's only reading though ... >> >> >> > > Do you run the rsync from a snapshot or from the 'live' filesystem? > The live one changes during zfs receive. I don't know if that has > anything to do with your problem, but rsync from a snapshot gives a > consistent backup anyway. > > BTW: It is probably more simple for you to test if the rsync is > related to the problem, than for other people to theorize about it here. > > Ronald. Also I don't believe using rsync either on the snapshot or the file system (read or write) should be related in any way to the hang I described. I let my cronjob rsync backups run wild without issues. When I say zfs commands, I don't mean random other commands on the zfs file system, but only the "zfs" command with a writing subcommand, such as destroy, recv, or snapshot, which obviously need some locking, and also send which locks some things, such as preventing the snapshot you are sending from being removed while you send it. Next time it hangs, just run something like: ps axl | grep zfs. If you see 2 zfs commands running at once that aren't parent/child of eachother, then you may have the same problem I described. If not (such as if you see your send + rsync at the same time), then it is something else.