On Wed, Aug 11, 2010 at 01:44:19PM -0500, Stephen Gelman wrote:
> On 08/11/2010 12:33 PM, John Rouillard wrote:
> > On Wed, Aug 11, 2010 at 10:23:59AM -0500, Stephen Gelman wrote:
> >> I am running BackupPC 3.1.0 on Nexenta.  It seems to be working for the
> >> most part.  I am having a problem with BackupPC_tarCreate.  I am trying
> >> to create a tar of a 30gb backup.  The tar I create ends up being 30gb,
> >> but when extracted it only takes up 5gb and is missing a lot of files.
> >> I can restore the missing files using the web interface, so I know that
> >> they are being backed up and that BackupPC has permission to access
> >> them.  Does anyone have any idea what's going on?  The only clue I have
> >> is that I repeatedly get "tar: Skipping to next header" when untaring
> >> the file.
> > Which tar are you using to do the restore: native solaris /usr/bin/tar
> > (or /usr/sbin/static/tar), gnu tar, pax? How are you supplying the 30
> > GB file to the restoring tar, stdin as a file on the command line ...?
> >
> > Do you have any compression in the picture? Also are you moving
> > between architectures or little to big endian machines?
> >
> Using gnu tar.  This happens both if I pipe the output of 
> BackupPC_createTar directly to tar and if I untar from the file.  More 
> specifically, the tar command I am using is "tar -xf - -C MYDIRECTORY".  
> No compression and the archive is staying on the same server.

I assume you are doing this locally on the nexenta box w/o ssh etc.
That should rule out blocking issues and network corruption
issues. But have you tried setting blocking to 20 explicitly in gnu
tar (I think that's what BackupPC_tarCreate uses).

Does:

   tar -xvf - -C MYDIRECTORY

change anything?

What are your arguments to BackupPC_tarCreate? You aren't redirecting
errors from BackupPC_tarCreate onto stdout using 2>&1 are you?

Can you restore a subset of the 30GB of data using:

   BackupPC_tarCreate ... -s share directory/path

where directory/path is a directory that is not being restored in the
30GB backup but is present in the backuppc web interface?

If you have pax installed does using it in place of tar produce better
diagnostics (e.g. why it doesn't look like file header)?

If you can get a smaller subset of restored files to produce the error
then you could look at the tar file and try to figure out what is
confusing tar. If you see a lot of nulls where there shouldn't be any,
maybe bad block factor despite what I said above?

-- 
                                -- rouilj

John Rouillard       System Administrator
Renesys Corporation  603-244-9084 (cell)  603-643-9300 x 111

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