From owner-freebsd-hackers Tue Mar 3 11:56:18 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA18471 for freebsd-hackers-outgoing; Tue, 3 Mar 1998 11:56:18 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from uni4nn.gn.iaf.nl (osmium.gn.iaf.nl [193.67.144.12]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id LAA18424 for ; Tue, 3 Mar 1998 11:56:02 -0800 (PST) (envelope-from wilko@yedi.iaf.nl) Received: by uni4nn.gn.iaf.nl with UUCP id AA08233 (5.67b/IDA-1.5 for hackers@freebsd.org); Tue, 3 Mar 1998 20:49:54 +0100 Received: (from wilko@localhost) by yedi.iaf.nl (8.8.7/8.6.12) id TAA01286; Tue, 3 Mar 1998 19:16:24 +0100 (MET) From: Wilko Bulte Message-Id: <199803031816.TAA01286@yedi.iaf.nl> Subject: Re: SCSI Bus redundancy... In-Reply-To: from Simon Shapiro at "Mar 3, 98 00:34:18 am" To: shimon@simon-shapiro.org Date: Tue, 3 Mar 1998 19:16:24 +0100 (MET) Cc: sbabkin@dcn.att.com, tlambert@primenet.com, jdn@acp.qiv.com, blkirk@float.eli.net, hackers@FreeBSD.ORG, grog@lemis.com X-Organisation: Private FreeBSD site - Arnhem, The Netherlands X-Pgp-Info: PGP public key at 'finger wilko@freefall.freebsd.org' X-Mailer: ELM [version 2.4ME+ PL32 (25)] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG As Simon Shapiro wrote... > > On 02-Mar-98 Wilko Bulte wrote: > ... > > > And apart from the work involved to get it implemented: how long would > it > > take a RAIDset to get re-organised/enlarged. Reason #1 for doing things > > like > > this is because you don't want downtime. And I don't want to think about > > some hardware failure (say a disk) halfway during this process. That > > would > > really result in a dis[k]array ;-) > > Nope... > > > 'Not everything that can be done should be done' > > Right!!! You must have tried it ;-) HP has something like this, but with a different implementation, I think it is called AutoRaid (?). They use RAID5 for 'cool' data and RAID1 for 'hot' data. This gives a nice compromise between cost (RAID1 is $$) and RAID5 (slower, especially on writes). They migrate between the raid levels based on data usage patterns. It was a very hot topic a couple of years ago, but in my experience this has cooled down quite a bit. Wilko _ ______________________________________________________________________ | / o / / _ Bulte email: wilko @ yedi.iaf.nl http://www.tcja.nl/~wilko |/|/ / / /( (_) Arnhem, The Netherlands - Do, or do not. There is no 'try' --------------- Support your local daemons: run [Free,Net,Open]BSD Unix -- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message