From owner-freebsd-hackers Sat Jun 14 15:19:16 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id PAA12832 for hackers-outgoing; Sat, 14 Jun 1997 15:19:16 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.50]) by hub.freebsd.org (8.8.5/8.8.5) with SMTP id PAA12824 for ; Sat, 14 Jun 1997 15:19:14 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id PAA14694; Sat, 14 Jun 1997 15:10:20 -0700 From: Terry Lambert Message-Id: <199706142210.PAA14694@phaeton.artisoft.com> Subject: Re: dump/restore with compression, roberto@keltia.freenix.fr To: rb@gid.co.uk (Bob Bishop) Date: Sat, 14 Jun 1997 15:10:20 -0700 (MST) Cc: terry@lambert.org, freebsd-hackers@FreeBSD.ORG In-Reply-To: from "Bob Bishop" at Jun 13, 97 07:09:27 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > >> I'd never use any compression -- except hardware-based like DAT's -- > >> because you can't recover much if your tape have a problem... I'm against > >> compressed file systems for that very reason too. [ ... block compression ... ] > You still get the phenomenon that I usually describe as 'uncompressing the > error' - your physical block contains more information when it's > compressed, so you lose more than in the uncompressed case even if you can > recover. Yes, but the error doesn't damage the entire filesystem or tape archive. You've lost the file either way if you have a media error, and spamming 2 blocks (assuming 50% compressed size) is not that much worse than spamming 1. If you were really paranoid about a particular files contents, such that one more block would "save your life", you would use rotating backups and an off-site fire-safe anyway. 8-). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.