From owner-freebsd-fs Tue Oct 13 22:59:53 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id WAA15235 for freebsd-fs-outgoing; Tue, 13 Oct 1998 22:59:53 -0700 (PDT) (envelope-from owner-freebsd-fs@FreeBSD.ORG) Received: from gatekeeper.tsc.tdk.com (gatekeeper.tsc.tdk.com [207.113.159.21]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id WAA15215; Tue, 13 Oct 1998 22:59:45 -0700 (PDT) (envelope-from gdonl@tsc.tdk.com) Received: from sunrise.gv.tsc.tdk.com (root@sunrise.gv.tsc.tdk.com [192.168.241.191]) by gatekeeper.tsc.tdk.com (8.8.8/8.8.8) with ESMTP id WAA09857; Tue, 13 Oct 1998 22:59:27 -0700 (PDT) (envelope-from gdonl@tsc.tdk.com) Received: from salsa.gv.tsc.tdk.com (salsa.gv.tsc.tdk.com [192.168.241.194]) by sunrise.gv.tsc.tdk.com (8.8.5/8.8.5) with ESMTP id WAA25064; Tue, 13 Oct 1998 22:59:26 -0700 (PDT) Received: (from gdonl@localhost) by salsa.gv.tsc.tdk.com (8.8.5/8.8.5) id WAA17612; Tue, 13 Oct 1998 22:59:24 -0700 (PDT) From: Don Lewis Message-Id: <199810140559.WAA17612@salsa.gv.tsc.tdk.com> Date: Tue, 13 Oct 1998 22:59:24 -0700 In-Reply-To: "Justin T. Gibbs" "Re: filesystem safety and SCSI disk write caching" (Oct 13, 11:16pm) X-Mailer: Mail User's Shell (7.2.6 alpha(3) 7/19/95) To: "Justin T. Gibbs" , Don Lewis Subject: Re: filesystem safety and SCSI disk write caching Cc: Terry Lambert , freebsd-fs@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Oct 13, 11:16pm, "Justin T. Gibbs" wrote: } Subject: Re: filesystem safety and SCSI disk write caching } >} This doesn't follow. If the cache is disabled, it doesn't matter if } >} the drive loses power due to hitting the reset button. We already } >} know that losing power on a drive that cached data will not work. } > } >I didn't hear the sound of any mechanical things spinning down. The } >machine just started going through its boot sequence. } } The drive will reinitialize to the 'power on state' if the power fluctuates } into a zone that might invalidate it's run-time state. It doesn't take a } very long spike for the drive's power-glitch sensor to go off. In this } case, dropping cached contents on the floor is much safer than attempting } to continue from an unknown state. If that's the reason for the problem that I saw, then the UPS the system was plugged into wasn't sufficient to prevent the problem. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message