Hi there,
On Mon, 16 Sep 2024, Daniel Berteaud wrote:
----- Le 21 Ao? 24, ? 2:02, backu...@kosowsky.org a ?crit :
First of all, the corruption seems almost definitely to be a disk
issue and not a backuppc issue.
I'm just configuring a new BackupPC v4.4 (on Debian, using packages
from the repo), ...
Does ZFS work on Linux now? That's a genuine question, not some way
of trying to goad ZFS lovers. I ask it because, last time I looked,
there were people here of the opinion that not only did it not work on
Linux but that it probably never would. Admittedly it was a while ago:
8<----------------------------------------------------------------------
Date: Tue, 2 Jun 2009 18:38:52 -0600
From: dan <danden...@gmail.com>
Subject: Re: [BackupPC-users] How to use backuppc with TWO HDD
To: ... <backuppc-users@lists.sourceforge.net>
...
ZFS on linux = bad. ZFS is a solaris thing and will be for some time.
someday *BSD will have stable ZFS but I doubt linux ever will. btrfs will
likely be in wide use which will serve many of the same purposes as ZFS.
...
8<----------------------------------------------------------------------
... encounter this kind of errors systematically. It's not a
corruption due to some hardware fault, but clearly a bug in
BackupPC.
As I've said before, but I'll repeat, I don't have any BackupPC axe to
grind but Mr. Kosowsky and I both think that what you're seeing looks
like filesystem corruption. You seem to be of the opinion that this
is not the explanation, and you might be right, but to convince me (at
least) unless I've missed something in your posts which makes the case
conclusively and to which you can point, then I think it must be up to
you to produce that evidence.
... This pool is used for other stuff (1 relatively busy mariadb
server in a VM, one Proxmox Backup Server storage pool), and
everything is working correctly. Only BackupPC is having issues.
The "everything is working correctly" part troubles me. I don't see
that you have evidence for that. The way I approach the logic of
troubleshooting, I'd say you haven't had problems with everything else
*yet*. And you might never have trouble with anything else, but that
is not the presence of evidence. It is the absence of evidence.
Looks like I'm not the only one affected, see
https://github.com/backuppc/backuppc/issues/494
Hmmm. That's on Linux as well - or more strictly, it was in April.
I tried 3 times to wipe and start from empty pool, but this comes
back everytime. So there's a bug in BackupPC. It might only be
triggered on ZFS (or maybe it's related to the speed on the
underlying storage, as this one is really the fastest I ever
used). But there's something. For the first time in more than 18
years of using BackupPC,
I've been running BackupPC for nearly as long as you have, and I've
never seen such errors. But I run ext4. It would take an awful lot
of persuasion and years of testing for me to switch to anything else.
Last time I tried one of the latest and greatest new filesystems, the
whole thing went belly up in days. I vowed never to do that again.
AFAICT so far, the best we can say is that the combination of BackuPC
and ZFS on Linux might be problematic. I can't say I'm surprised, but
I can say that we really don't yet know where your problem lies. So
far, I only know of two people running BackupPC on ZFS on Linux. [*]
Both have posted to Github issue 494. Unless there's some lurker here
who's keeping very quiet, in my view as I said above only you and that
other person are in a position in which they will be able to collect
evidence to identify BackupPC as the culprit. Evidence, not anecdote.
Also I'd say that in a previous post you described a whole lot of what
appeared to me to be completely unnecessary thrashing of storage media
in (something like) the interests of reliability. My feeling at that
time was that you were making a rod for your own back and I still feel
that way. I kept quiet at the time on grounds of tranquility on this
list, but I believe that you have made things much more complex than
necessary and I'd like to suggest a test...
I think I cannot trust my backups anymore. ... very worrying.
There we can agree. My sugested test is that you fire up a system
using ext4, don't do anything fancy with it, run it in parallel with
your ZFS version, and then sit back and see what happens. There may
be alternatives, such as ditching Linux and trying Solaris. I could
only take a back seat if you did something like that.
In your position, not that I'd ever let myself get into that position,
I would try ext4 because it's easy and it's never given any trouble.
[*]
There was a mention in April, see "Problems cropping up with backups"
but I don't know if we ever knew if the TrueNAS host is running Linux.
