From owner-freebsd-fs@FreeBSD.ORG Wed May 24 12:18:01 2006 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 199D916A447 for ; Wed, 24 May 2006 12:18:01 +0000 (UTC) (envelope-from anderson@centtech.com) Received: from mh2.centtech.com (moat3.centtech.com [207.200.51.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7607C43D4C for ; Wed, 24 May 2006 12:18:00 +0000 (GMT) (envelope-from anderson@centtech.com) Received: from [10.177.171.220] (neutrino.centtech.com [10.177.171.220]) by mh2.centtech.com (8.13.1/8.13.1) with ESMTP id k4OCHvAd083891; Wed, 24 May 2006 07:17:59 -0500 (CDT) (envelope-from anderson@centtech.com) Message-ID: <44744EF8.2000000@centtech.com> Date: Wed, 24 May 2006 07:18:00 -0500 From: Eric Anderson User-Agent: Thunderbird 1.5.0.2 (X11/20060506) MIME-Version: 1.0 To: Kris Kennaway References: <4473FA8F.6050102@outblaze.com> <20060524061848.GA58522@xor.obsecurity.org> In-Reply-To: <20060524061848.GA58522@xor.obsecurity.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV 0.87.1/1479/Wed May 24 00:17:23 2006 on mh2.centtech.com X-Virus-Status: Clean Cc: freebsd-fs@freebsd.org Subject: Re: Access to UFS stuck during snapshot. X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 May 2006 12:18:01 -0000 Kris Kennaway wrote: > On Wed, May 24, 2006 at 02:17:51PM +0800, Kent Ho wrote: >> Hi, >> >> I having problems accessing file system during snapshot runs. snapshot >> takes approximately 10 to 20 mins to run. >> >> During that time access to files in the file system are blocked until >> the snapshot has completed. Lot of processes was stuck and piles up on >> the fs. >> >> This fs stores mailboxes and it's accessed 24/7. This is similar to >> what described in this thread. >> >> http://www.freebsd.org/cgi/getmsg.cgi?fetch=14968+0+/usr/local/www/db/text/2006/freebsd-fs/20060312.freebsd-fs >> >> Has this been improved or fixed in recent releases, I see a bunch of >> fixes in march? any possible work around? any alternatives or >> recommendations? Looking for high availability fs with snapshots. > > It's by design. > > Kris I found that making the .snap directories permissions 0700, and then making a subdirectory under the .snap that stores the actual snapshots helped, as long as I did not make any stat() calls to the snapshot file that was in snaplk state. Kris - you've had your head deep in the snapshot spaghetti recently - is this blocking just a matter of the locking on the snapshot file and a stat() call blocking on it, which causes an upward locking to the root dir of the filesystem? Could this be avoided by 'hiding' the snapshot file while a snapshot is in progress? I have been tinkering with hiding the snapshot directory during snapshot creation, but I don't have any results of anything yet, still too early. I'm a wannabe hacker, so my progress is slow. Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------