From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <0c4c302ea99c108b3c6ce00e46f2b428@plan9.bell-labs.com> From: David Presotto To: 9fans@cse.psu.edu Subject: Re: [9fans] dd-induced hangs In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="upas-xydrlfkmumidsxxvgyhmlrxjww" Date: Mon, 7 Jul 2003 18:26:39 -0400 Topicbox-Message-UUID: ed672ed0-eacb-11e9-9e20-41e7f4b1d025 This is a multi-part message in MIME format. --upas-xydrlfkmumidsxxvgyhmlrxjww Content-Disposition: inline Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit smells like one to me also. We should be able to recreate it. --upas-xydrlfkmumidsxxvgyhmlrxjww Content-Type: message/rfc822 Content-Disposition: inline Received: from plan9.cs.bell-labs.com ([135.104.9.2]) by plan9; Mon Jul 7 18:07:24 EDT 2003 Received: from mail.cse.psu.edu ([130.203.4.6]) by plan9; Mon Jul 7 18:07:22 EDT 2003 Received: by mail.cse.psu.edu (CSE Mail Server, from userid 60001) id 2B6AF19C65; Mon, 7 Jul 2003 18:07:13 -0400 (EDT) Received: from psuvax1.cse.psu.edu (psuvax1.cse.psu.edu [130.203.6.6]) by mail.cse.psu.edu (CSE Mail Server) with ESMTP id 29CBB19C46; Mon, 7 Jul 2003 18:07:09 -0400 (EDT) X-Original-To: 9fans@cse.psu.edu Delivered-To: 9fans@cse.psu.edu Received: by mail.cse.psu.edu (CSE Mail Server, from userid 60001) id E66FB19C55; Mon, 7 Jul 2003 18:06:08 -0400 (EDT) Received: from fbsd.cpsc.ucalgary.ca (fbsd.cpsc.ucalgary.ca [136.159.7.68]) by mail.cse.psu.edu (CSE Mail Server) with ESMTP id F0DAC19C5C for <9fans@cse.psu.edu>; Mon, 7 Jul 2003 18:06:07 -0400 (EDT) Received: from fbsd.cpsc.ucalgary.ca (localhost.localdomain [127.0.0.1]) by fbsd.cpsc.ucalgary.ca (8.12.8/8.12.8) with ESMTP id h67M5xeH004849 for <9fans@cse.psu.edu>; Mon, 7 Jul 2003 16:05:59 -0600 Received: from localhost (mirtchov@localhost) by fbsd.cpsc.ucalgary.ca (8.12.8/8.12.8/Submit) with ESMTP id h67M5xeN004845 for <9fans@cse.psu.edu>; Mon, 7 Jul 2003 16:05:59 -0600 X-Authentication-Warning: fbsd.cpsc.ucalgary.ca: mirtchov owned process doing -bs From: andrey mirtchovski To: 9fans@cse.psu.edu Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Subject: [9fans] dd-induced hangs Sender: 9fans-admin@cse.psu.edu Errors-To: 9fans-admin@cse.psu.edu X-BeenThere: 9fans@cse.psu.edu X-Mailman-Version: 2.0.11 Precedence: bulk Reply-To: 9fans@cse.psu.edu List-Id: Fans of the OS Plan 9 from Bell Labs <9fans.cse.psu.edu> List-Archive: Date: Mon, 7 Jul 2003 16:05:59 -0600 (MDT) X-Spam-Status: No, hits=-0.4 required=5.0 tests=USER_AGENT_PINE,X_AUTH_WARNING version=2.55 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) doing 'dd -if /dev/sdC0/arenas -of /dev/sdD0/arenas -bs 8192' hangs the system with 100% reproducibility (though each occurs after a different period of time). the arenas partition is 60GB. running the same command on smaller partitions (fossil, 13GB; isect, 3GB; 9fat, 10MB; nvram, 512B) completes successfully (at 15MB/s transfer rates). none of the processes on the machine are able to do any work, the console is updated when I hit a key (interrupts are processed), but rc doesn't get a chance to print a prompt. the load on the machine before the event wasn't high, but stats showed it peaking at 8000 just before the machine hung. things like ^T^Tp work, and in fact I've captured ^T^Tp, ^T^Tq and ^T^Tx if anyone is interested (^T^Ts doesn't work anymore? it's in the man page). starting the debugger (^T^TD) caused the machine to hang completely and irreversibly. it smells like a race, but my nose isn't that good to be absolutely sure :) andrey ps: i've turned dma off now and am runing the same thing again, but dma off means i'll be able to verify whether the command completed early tomorrow morning. --upas-xydrlfkmumidsxxvgyhmlrxjww--