From owner-freebsd-questions Tue Jul 25 14:28:20 2000 Delivered-To: freebsd-questions@freebsd.org Received: from ptavv.es.net (ptavv.es.net [198.128.4.29]) by hub.freebsd.org (Postfix) with ESMTP id A8BA037B5C7 for ; Tue, 25 Jul 2000 14:28:14 -0700 (PDT) (envelope-from oberman@ptavv.es.net) Received: from ptavv.es.net (localhost [127.0.0.1]) by ptavv.es.net (8.10.1/8.10.1) with ESMTP id e6PLSBU26809; Tue, 25 Jul 2000 14:28:11 -0700 (PDT) Message-Id: <200007252128.e6PLSBU26809@ptavv.es.net> To: "Jason C. Wells" Cc: Meagan Jia Pi , freebsd-questions@FreeBSD.ORG Subject: Re: Backup Solution In-reply-to: Your message of "Tue, 25 Jul 2000 13:43:35 PDT." Date: Tue, 25 Jul 2000 14:28:11 -0700 From: "Kevin Oberman" Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Date: Tue, 25 Jul 2000 13:43:35 -0700 (PDT) > From: "Jason C. Wells" > Sender: owner-freebsd-questions@FreeBSD.ORG > > On Tue, 25 Jul 2000, Meagan Jia Pi wrote: > > > I don't quite understand how 490GB data can fit in a 70GB DLT tape. How do > > you > > do that? You are right, if such a big compression can be achieved, a robot > > is not necessary > > al all! Great news! > > OK. Take a 35 GB DLT with a drive that does 2-1 compression. That gives 70 > GB on a tape. No, it does not! More and more, files on computers are already compressed. The Veritas backup software I use on one system shows the compression ratio you are really getting and I typically get about 1.2:1, a long way from 2:1. This yields 42 GB on a 35 GB tape. I think that advertising the capacity of tapes as twice what they really are because they are compressed is false advertising! R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message