From owner-freebsd-current Tue Jan 12 22:10:28 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id WAA20103 for freebsd-current-outgoing; Tue, 12 Jan 1999 22:10:28 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from apollo.backplane.com (apollo.backplane.com [209.157.86.2]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id WAA20090 for ; Tue, 12 Jan 1999 22:10:26 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.1/8.9.1) id WAA07980; Tue, 12 Jan 1999 22:09:49 -0800 (PST) (envelope-from dillon) Date: Tue, 12 Jan 1999 22:09:49 -0800 (PST) From: Matthew Dillon Message-Id: <199901130609.WAA07980@apollo.backplane.com> To: Mattias Pantzare Cc: current@FreeBSD.ORG Subject: Re: Enabling Softupdates with symlinks? Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG : :Realy? Why would the power dissapear from the HD when I press the _reset_ :button? : :Is it not a big propability that the HD is writing on a sector at a power :failure on a loaded server? The disks usualy survive a power failure with no :problems att all. If the drive happens to be in the middle of a write during a power failure, it is virtually guarenteed to loose at least one sector. Seagates will tend to loose one or two. Quantums will tend to loose hundreds of sectors - we've completely destroyed quantums that way. Occassionally a power failure will destroy the motherboard but not the platter - that has happened to us on two occasions, where the disk's motherboard is dead and we can pop it and replace it with another and bring the drive back to life well enough that we can read the data off it. Typically, a heavily loaded server is weighted towards doing more reads on a drive then writes. A power failure during a read is usually non-destructive. Most of the time power failures do not damage the disks. But since it's happened to us on a number of equations, the chances are obviously not 0. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message