From owner-freebsd-current Tue Aug 10 21:10:13 1999 Delivered-To: freebsd-current@freebsd.org Received: from dorifer.heim3.tu-clausthal.de (dorifer.heim3.tu-clausthal.de [139.174.243.252]) by hub.freebsd.org (Postfix) with ESMTP id 1C8D914DFE for ; Tue, 10 Aug 1999 21:10:06 -0700 (PDT) (envelope-from olli@dorifer.heim3.tu-clausthal.de) Received: (from olli@localhost) by dorifer.heim3.tu-clausthal.de (8.8.8/8.8.8) id GAA12393 for freebsd-current@FreeBSD.ORG; Wed, 11 Aug 1999 06:10:04 +0200 (CEST) (envelope-from olli) Date: Wed, 11 Aug 1999 06:10:04 +0200 (CEST) From: Oliver Fromme Message-Id: <199908110410.GAA12393@dorifer.heim3.tu-clausthal.de> To: freebsd-current@FreeBSD.ORG Subject: Re: wd0: interrupt timeout (status 58 error 1) Organization: Administration Heim 3 Reply-To: freebsd-current@FreeBSD.ORG MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: TIN [version 1.2 RZTUC(3) PL2] Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Doug White wrote in list.freebsd-current: > On Tue, 10 Aug 1999, Oliver Fromme wrote: > > > > Do those drives happen to be IBM DeskStar drives? > > They spin down automatically when they have not been turned > > off for about a week, in order to clean the heads. > > It's a feature. > > You've got to be kidding. No, I'm serious, that behaviour is a fact, and it's documented. > That makes them totally useless for server > operation The IBM DeskStar series is for desktop use, not for Servers. (Apart from the fact that I wouldn't use IDE drives for real servers anyway.) > -- at some random time every week, down goes your server for a > few minutes. :( No, only a few seconds. If there doesn't happen to be a disk access in that time interval, you won't notice at all. Other- wise you'll get that log message from the driver. This is the background of that feature: The IBM DeskStar disks are specifically designed for at least one on/off cycle per day. The "landing zones" where the heads are parked consist of a special layer that cleans the heads. If the disk is not switched off for a long period, the disk enforces a short spin- down + spin-up to clean the disk heads periodically. All of this is explained in more detail in a white paper of IBM, I think it is available from IBM's site. IBM's server disks (UltraStar) are designed for much fewer on/off cycles (in fact IBM recommends that they should not be used in desktops that are switched off very often, e.g. for power-saving or noise-reduction). They don't have that cleaning layer (and they don't need it). That's one of the reasons why they're more expensive. Bottom line: For a server, buy server disks. If you use cheap IBM DeskStar disks in a server, you won't get 100% availability (rather 100% minus a few seconds per week). Regards Oliver -- Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany (Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de) "In jedem Stück Kohle wartet ein Diamant auf seine Geburt" (Terry Pratchett) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message