Date: Wed, 10 Mar 1999 14:30:31 -0500 (EST) From: "Crist J. Clark" <cjc@cc942873-a.ewndsr1.nj.home.com> To: babolo@links.ru (Aleksandr A.Babaylov) Cc: cjclark@home.com, pete@bowtie.nl, hackers@FreeBSD.ORG Subject: Re: using dd to make backup of disk? Message-ID: <199903101930.OAA01900@cc942873-a.ewndsr1.nj.home.com> In-Reply-To: <199903101903.WAA25960@aaz.links.ru> from "Aleksandr A.Babaylov" at "Mar 10, 99 10:03:49 pm"
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Aleksandr A.Babaylov wrote, > Crist J. Clark writes: > > Peter Weijmarshausen wrote, > > > Before you all start mailing me about how stupid it > > > is to use dd as a backup mechanism: I use this in > > > order to maintain an instant bootable backup. > > > So if the primary disk crashes I unplug it, reboot the > > > system and I have a working system again. > > > > Why is, > > > > # cd backupfs > > # dump -0af - origfs | restore -rf - > > > > Any less 'instant?' And 'dump' is meant to handle live filesystems. > dd is much faster. > boot codes and disk labels are not copied by dump|restore > only ufs (and ext2fs) can be copied by dump|restore That idea kind of scares me. You are assuming the two disks involved have identical geometries and characteristics when copying a disklabel. It just seems to me that dump|restore is a much safer alternative. Write the bootblocks and disklabel the backup manually once, then backup filesystems periodically. How often would the bootsectors and label change? -- Crist J. Clark cjclark@home.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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