From bacula-users-admin@lists.sourceforge.net Mon Oct 20 23:44:13 2003 Return-Path: Received: from sc8-sf-list2.sourceforge.net (lists.sourceforge.net [66.35.250.206]) by matou.sibbald.com (8.11.6/8.11.6) with ESMTP id h9KLiDY13657 for ; Mon, 20 Oct 2003 23:44:13 +0200 Received: from sc8-sf-list1-b.sourceforge.net ([10.3.1.13] helo=sc8-sf-list1.sourceforge.net) by sc8-sf-list2.sourceforge.net with esmtp (Exim 3.31-VA-mm2 #1 (Debian)) id 1ABhpS-00013k-00; Mon, 20 Oct 2003 14:44:42 -0700 Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Cipher TLSv1:DES-CBC3-SHA:168) (Exim 3.31-VA-mm2 #1 (Debian)) id 1ABhnp-0007qu-00 for ; Mon, 20 Oct 2003 14:43:01 -0700 Received: from bast.unixathome.org ([66.11.174.150] ident=postfix) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.22) id 1ABfiR-0002Iv-Q8 for bacula-users@lists.sourceforge.net; Mon, 20 Oct 2003 12:29:19 -0700 Received: from wocker (wocker.unixathome.org [192.168.0.99]) by bast.unixathome.org (Postfix) with ESMTP id 258913F53 for ; Mon, 20 Oct 2003 15:25:33 -0400 (EDT) From: "Dan Langille" To: bacula-users@lists.sourceforge.net MIME-Version: 1.0 Message-ID: <3F93FF4E.14552.13ACB682@localhost> Priority: normal X-mailer: Pegasus Mail for Windows (v4.02a) Content-type: text/plain; charset=US-ASCII Content-description: Mail message body X-Spam-Score: 0.0 (/) X-Spam-Report: 0.0/5.0 Spam Filtering performed by sourceforge.net. See http://spamassassin.org/tag/ for more details. Report problems to https://sf.net/tracker/?func=add&group_id=1&atid=200001 Subject: [Bacula-users] FreeBSD - large backups to tape Sender: bacula-users-admin@lists.sourceforge.net Errors-To: bacula-users-admin@lists.sourceforge.net X-BeenThere: bacula-users@lists.sourceforge.net X-Mailman-Version: 2.0.9-sf.net Precedence: bulk List-Help: List-Post: List-Subscribe: , List-Id: Bacula user's email list for support and discussions List-Unsubscribe: , List-Archive: Date: Mon, 20 Oct 2003 15:29:18 -0400 Content-Transfer-Encoding: 8bit Kern and I have been working on a FreeBSD/Bacula problem. He's asked me to post this to the list. The problem was within the FreeBSD pthreads library. A solution has been found. PROBLEM DESCRIPTION: The FreeBSD pthreads library does not properly handle End Of Tape. This problem will be fixed in FreeBSD 4.9. The bug results in more data being written to the tape than could be read. Any backup which involved more than one tape would be incomplete. DEMONSTRATION: To demonstrate the problem, tapetest.c can be obtained from http://www.freebsd.org/cgi/query-pr.cgi?pr=56274 This tests without pthreads: * If you build this program with: * * c++ -g -O2 -Wall -c tapetest.c * c++ -g -O2 -Wall tapetest.o -o tapetest * * Procedure for testing tape * ./tapetest /dev/your-tape-device * rewind * rawfill * rewind * scan * * The output will be something like: * * ======== * Rewound /dev/nsa0 * *Begin writing blocks of 64512 bytes. * ++++++++++++++++++++ ... * Write failed. Last block written=17294. stat=0 ERR=Unknown error: 0 * weof_dev * Wrote EOF to /dev/nsa0 * *Rewound /dev/nsa0 * *Starting scan at file 0 * 17294 blocks of 64512 bytes in file 0 * End of File mark. * End of File mark. * End of tape * Total files=1, blocks=17294, bytes = 1115670528 * ======== * * which is correct. Notice that the return status is * 0, while in the example below, which fails, the return * status is -1. This tests with pthreads: * If you build this program with: * * c++ -g -O2 -Wall -pthread -c tapetest.c * c++ -g -O2 -Wall -pthread tapetest.o -o tapetest * Note, we simply added -pthread compared to the * previous example. * * Procedure for testing tape * ./tapetest /dev/your-tape-device * rewind * rawfill * rewind * scan * * The output will be something like: * * ======== * Rewound /dev/nsa0 * *Begin writing blocks of 64512 bytes. * +++++++++++++++++++++++++++++ ... * Write failed. Last block written=17926. stat=-1 ERR=No space left on device * weof_dev * Wrote EOF to /dev/nsa0 * *Rewound /dev/nsa0 * *Starting scan at file 0 * 17913 blocks of 64512 bytes in file 0 * End of File mark. * End of File mark. * End of tape * Total files=1, blocks=17913, bytes = 1155603456 * ======== * * which is incroorect because it wrote 17,926 blocks but read * back only 17,913 blocks If you get the same number of blocks written and read WHEN using pthreads, then you've been correctly patched. SOLUTION: For FreeBSD prior to 4.9, you have two choices to ensure proper backups. These instructions assume you are familiar with patching FreeBSD and already have the FreeBSD source code installed on your machine. 1 - cvsup and build your system to FreeBSD 4.8-STABLE 2 - Apply this patch. http://www.freebsd.org/cgi/cvsweb.cgi/src/lib/libc_r/uthread/uthread_write.c.diff?r1=1.16.2.6&r2=1.16.2.7 To apply the patch, follow these instructions as root. fetch -o pthread.diff http://www.freebsd.org/cgi/cvsweb.cgi/src/lib/libc_r/uthread/uthread_write.c.diff?r1=1.16.2.6\&r2=1.16.2.8 cd /usr/src/lib/libc_r/uthread/ patch < /path/to/pthread.diff cd .. make all install I recommend restarting Bacula. TESTING: I suggest running tapetest on your patched system and then conducting a backup which spans two tapes. Restore the data and compare to the original. If not identical, please let us know. Thanks -- Dan Langille : http://www.langille.org/ ------------------------------------------------------- This SF.net email is sponsored by OSDN developer relations Here's your chance to show off your extensive product knowledge We want to know what you know. Tell us and you have a chance to win $100 http://www.zoomerang.com/survey.zgi?HRPT1X3RYQNC5V4MLNSV3E54 _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users