[2549] in SIPB-AFS-requests
Re: RFD - Backup system: tape retiring, system overhaul/upgrade
daemon@ATHENA.MIT.EDU (mhpower@MIT.EDU)
Tue Nov 19 20:03:54 1996
From: mhpower@MIT.EDU
Date: Tue, 19 Nov 1996 20:03:34 -0500
To: sit@MIT.EDU
Cc: star-maintainers@MIT.EDU
>could implement a labeling scheme that goes something like:
>
> HOST exb-##
> ^^^^ ^^^^^^
> charon 10--19
> bloom-picayune 20--29
> anxiety-closet 30--39
> bloom-beacon 40--49
> senator-bedfellow 50--59
> penguin-lust 60--69
Although the numbering scheme seems ok, I should mention that the news
servers aren't backed up using the osu backup system, and there are
no plans to start doing so. In fact, I suspect it's more likely that
we'd start backing up the local disks of the AFS servers, since I
think (although I hope I'm mistaken) that they have important data
that frequently changes and isn't backed up to tape either directly or
indirectly (e.g., /usr/afs/db). It's possibly even more likely that
we'd start backing up one of the local disks on zsr. (Admittedly,
this isn't an issue that belongs on the star-maintainers list.)
On servers where there's only a small volume (~10 Mb or less) of
important files that frequently change and don't already also exist in
AFS, another possibility is to automatically back up those files to
AFS so that they're then included in the AFS backups. Depending on
what the files are, it might be useful to encrypt them with PGP first.
Disk-to-disk partial backups have the disadvantage that restoring a
system after a disk failure requires some knowledge of how local
directories are supposed to be set up. Also, there's the disadvantage
that someone might've upgraded to a new version of ls, without
realizing that /bin/ls wasn't tagged as an often-changing file. The
main advantages are less system load during the time the backup runs,
and less total tape-loading/changing/labeling workload, which probably
makes it more likely that the needed backups actually get done.
One final concern: when we've changed components of the backup
software in the past, we've noticed (sometimes quite a while
afterward) problems with the files in /usr/local/backup/db/exclude not
actually being excluded from the backup. If you install a new version,
please test it initially by backing up only a partition that doesn't
need to have any files excluded, creating some test exclude entries (I
think the main different cases are: isolated filenames, full
pathnames, and pathname patterns that end with "/*"), and listing the
tape afterwards to make sure that the exclude entries worked.
Matt
