Amanda-Users

Re: NFS mount tar incremental problem

2008-04-15 21:12:45
Subject: Re: NFS mount tar incremental problem
From: Jordan Desroches <jordan.d.desroches AT Dartmouth DOT EDU>
To: amanda-users AT amanda DOT org
Date: Tue, 15 Apr 2008 19:58:32 -0400
I have not tested it yet myself, but version 1.2 of gnutar was released yesterday (see http://www.gnu.org/software/tar/#TOCreleases ) and of particular interest is this feature (quoted from the page):

"New options --no-check-device, --check-device.

The --no-check-device option disables comparing device numbers during preparatory stage of an incremental dump. This allows to avoid creating full dumps if the device numbers change (e.g. when using an LVM snapshot).

The --check-device option enables comparing device numbers. This is the default. This option is provided to undo the effect of the previous --no-check-device option, e.g. if it was set in TAR_OPTIONS environment variable."


Best,

Jordan

On Mar 26, 2008, at 11:28 AM, Gene Heskett wrote:

On Tuesday 25 March 2008, Gene Heskett wrote:
On Tuesday 25 March 2008, Dustin J. Mitchell wrote:
On Tue, Mar 25, 2008 at 11:31 AM, Gene Heskett <gene.heskett AT verizon DOT net >

wrote:
And I, like an idiot, didn't notice we were discussing an NFS problem, which may be another manifestation of the same problem, but that patch does not address what happens when the linux device mapper decides to
move an LVM2 volume from 253,0 ro 254,0.

The patch JLM posted won't fix it, but his proposed command-line option
will.

Post please, I don't believe I've seen it. I had some email problems over the weekend due to my / partition being in bad need of an fsck. 2.6.24
running tickless was a friggin nightmare.

Thats why I'm asking about Schiling Tar, aka S-Tar. Does that fix the
problem?, and can amanda use it?

Yes, but its semantics are very different from GNU Tar -- it's not a
drop-in fix.

I was afraid of that.

The ultimate weapon of course in any philosophical war, which this is, is to fork tar and fix it if STar isn't usable. At this point, and while I'm not capable of doing it, I'm not a bit allergic to the fork idea. Its bitten me so often that I'll alpha test anybodies efforts in that
regard. Gleefully.

Sure, but threatening a fork is un-diplomatic, and not called for just
yet.  Let's start with a concerted public-relations effort :)

I doubt if my messages on the subject were the only ones they got, and from the attitude displayed in the replies I got, a fork IS the next step. They are immovable on the subject. They consider that a change in the device mapping numbers are prima-faci evidence of a stolen tar file trying to be recovered to a disk that they don't belong to. A huge security problem in
their view.

Humm, didn't we have some scripts that could inspect and repair the
index files when this happened? Probably lost when I woke up one morning
and found my well developed FC6 install wasn't re-bootable, LSN0 on
/dev/hda had one non-zero byte left in it.

Yep -- it's called tar-snapshot-edit, and it's available in recent
releases of GNU Tar.  Just google for it.

I'll do that, got it.

Thanks, Dustin.

To continue this thread I have now subscribed to the bug-tar list about 24 hours ago, but two messages I've sent have been bounced. So I tried to
re-confirm since I still had the message, and that bounced with
the 'confirmation string invalid'.

I'm about up to my eyeballs in gnu BS, its not worth the effort to talk to
those fence posts.

I'd write a cron script to hit them every 10 minutes, but I don't need the bounces. If you can get in, tell them to fix their (*&^$ mail server to
accept messages from somebody newly subscribed.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
YOU HAVE AN I/O ERROR -> Incompetent Operator error


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