From owner-freebsd-questions@FreeBSD.ORG Wed Dec 8 16:09:29 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A26D516A4CE for ; Wed, 8 Dec 2004 16:09:29 +0000 (GMT) Received: from www16.your-server.de (www16.your-server.de [213.133.104.16]) by mx1.FreeBSD.org (Postfix) with SMTP id 23E7643D39 for ; Wed, 8 Dec 2004 16:09:28 +0000 (GMT) (envelope-from galtmann@las-cad.com) Received: (qmail 26035 invoked by uid 1825); 8 Dec 2004 16:09:27 -0000 Received: from galtmann@las-cad.com by www16.your-server.de by uid 502 with qmail-scanner-1.22 (clamdscan: 0.71. Clear:RC:1(217.235.115.115):. Processed in 0.131167 secs); 08 Dec 2004 16:09:27 -0000 X-Qmail-Scanner-Mail-From: galtmann@las-cad.com via www16.your-server.de X-Qmail-Scanner: 1.22 (Clear:RC:1(217.235.115.115):. Processed in 0.131167 secs) Received: from pd9eb7373.dip0.t-ipconnect.de (HELO asterix.las-cad.local) (217.235.115.115) by www16.your-server.de with SMTP; 8 Dec 2004 16:09:26 -0000 Received: from [192.168.98.23] (mnch-d9ba329b.pool.mediaWays.net [217.186.50.155]) (authenticated bits=0)iB8G91F8027500 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 8 Dec 2004 17:09:02 +0100 (CET) (envelope-from galtmann@las-cad.com) Date: Wed, 08 Dec 2004 17:08:55 +0100 From: Georg Altmann To: freebsd-questions@freebsd.org Message-ID: In-Reply-To: References: X-Mailer: Mulberry/3.1.6 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Scanned-By: MIMEDefang 2.35 Subject: Re: semaphore problem with Bakbone's Netvault on FreeBSD 4.10 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Dec 2004 16:09:29 -0000 In the meantime Bakbone support managed to send me a working (binary) patch fixing the problem and I was asked by Bakbone to post this information. So, if you experience the problem described below, please contact Bakbone support. Best regards, Georg Altmann --On Montag, November 22, 2004 19:33:51 +0100 Georg Altmann wrote: > I have a problem running the backup software Netvault from Bakbone > (http://www.bakbone.com) under FreeBSD 4.10. > We are using Netvault to make backups of two servers and several > workstations in our network. Backups are first staged to disk and later > transferred to an ADIC FastStor 2 (LTO 1) library. > > The problem occurs when the backup is transferred from disk to tape and > if the backup job spans multiple tapes (not virtual media!): Netvault > recognizes the end-of-media, loads a new media for the job and then hangs > endlessly trying to write to the new media. > > Bakbone claims, that this is a problem with SysV shared memory and > semaphores in FreeBSD (and therefore not their software). Their support > also sent me a patch for Netvault (unfortunately not a binary one, so I > cannot test it) which is allegedly known to work around the problem. I > attached it below. Note the added "#if defined(PLATFORM_FREEBSD)" bits in > the code. To my understanding, the patched code polls the semaphore > instead of waiting for it. > Please also note, that I configured Netvault to use network sockets > instead of shared mem for the transfer and the problem persists (I did > this by only selecting "TCP Data Transfer" in the configure device tab > for both the tape and the virtual library and by adding [Data > Channels]\nForce Sockets=TRUE to configure.cfg as proposed by Bakbone > support, for anyone familiar with netvault). So I assume, the problem is > really only related to semaphores and not at all to shared memory(?). > > I hope that someone can guess from the code if this really leads to a > deadlock because of a FreeBSD bug in SysV sempaphore handling. > I have already skimmed FreeBSD PRs for semaphore bugs, but no post really > seemed related to this specific problem (see > http://www.freebsd.org/cgi/query-pr-summary.cgi?category=&severity=&prior > ity=&class=&state=&sort=none&text=semaphore&responsible=&multitext=&origi > nator=&closedtoo=on&release=). So, maybe somebody is able to make clear > whether I should urge Bakbone to fix their buggy software or look for a > patch for the FreeBSD kernel and/or libraries. [ removed ] -- >-------------------<>-----------------------------< > Georg Altmann <> Phone +49 (0)89 17809328 < > LAS-CAD GmbH <> Fax +49 (0)89 172594 < > Brunhildenstr. 9 <> e-mail galtmann@las-cad.com < > D-80639 Munich <> backup george@george-net.de < > Germany <> http://www.las-cad.com < >-------------------<>-----------------------------<