[leafnode-list] Re: backup or migration strategy
Matthias Andree
matthias.andree at gmx.de
Tue Sep 18 20:38:17 CEST 2012
Am 17.09.2012 23:18, schrieb Thufir:
> Looking at a thread on backups:
>
> http://thread.gmane.org/gmane.network.leafnode/3287
>
> So that when the hard drive fails or fills up, you can just tar the spool?
Yes, you can.
It is, however, important that tar, pax, cpio, or whichever tool you
use, is (A) capable of, and (B) instructed to save and restore
hard links as hard links (rather than just copies). Each article has
only one file (inode, technically speaking) with multiple names (= hard
links). This makes sure that we do not waste space (inodes and blocks)
on the file systems while maintaining fast access both by article number
and by message ID.
If the tool was incapable and/or improperly configured, texpire -r is
required - after unpacking the archive - to restore the hard links (and
can take quite a while to run in this case).
Also, with leafnode-1 versions, texpire -r is advised after untarring
the spool if and only if the configured name of the spooldir has changed
(because it was, unfortunately, part of the hash for access by message.ids).
It is also generally advisable to use a file system that uses hashes or
trees to manage its files per directory.
> Or, perhaps it would make sense configure leafnode to work off a
> secondary hard drive, although perhaps that would require configuring /
> var with symlinks?
While possible, what is the point?
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