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On Sun, Mar 02, 2008 at 05:51:06PM +1300, Mark Kirkwood wrote: |
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> I wrote: |
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>> |
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>> |
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>> If you want to back the system up while it is running (in particular /), |
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>> then you need to use a tool that understands how to create a backup image |
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>> that is valid (i.e will boot) - something like xfsdump, *dumpe2fs* etc or |
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>> smart tar/dump based tools like Amanda. |
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> Hmm - dunno what I was thinking there - 'dumpe2fs' is completely wrong, |
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> should have written 'dump', sorry! |
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If you do backup live filesystems/data then dump is on par with dd; both |
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read from the underlying device and might bypass the kernel's page cache. |
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Ie., there might be unwritten data cached thats not on disk yet. |
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Tar/rdiff-backup/etc reads through the pagecache and avoids this problem. |
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The dump people talk a bit about this themselves on |
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http://dump.sourceforge.net/isdumpdeprecated.html |
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Note I dont want to dis dump, backing up live filesystems is just tricky |
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(depending on your consistency requirements :) and dump adds another |
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level to that. |
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Cheers, |
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Rasmus |
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-- |
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