Re: [Veritas-bu] Data Corruption (How to Troubleshoot)

Hi,

I have backed up 280-350GB tarballs and restored without an issue (butlinux<->linux).

I would recommend you copy the tarball from windows -> to the media serverand check the md5sum, then, copy from the media server to where you arerestoring it to and check the md5sum. If everything is good then you needto start looking at the netbackup software/tape/buffers/cables/etc.

I have actually seen corruption on a LINUX media server because of a tcpoffload setting on the network interface being set incorrectly. All ofthe data was corrupted passing through it and NetBackup did not reportany errors, pretty nasty-- so try what I mentioned below and report back.

Follow the checksum as it goes through the various servers. If you copyit from the source and there is an md5 mismatch then you know the serverhas bad memory/disk/etc.

Also, if the file shrinks, it will say "file has shrunk, padding withzeroes" - if it increases though I am not sure if it says anything in thelogs.


Justin.

On Fri, 11 Sep 2009, Jorge Fábregas wrote:

Hello guys,

I have this 20GB TAR file (created with 7zip) on a Windows machine. I perform
a backup of this TAR file and everything goes ok.  When I restored the file
on a Linux host I first noticed the file size was off by a few bytes and I'm
unable to extract it. I then verified with md5sum and I get a different hash
from that of the original file (on Windows I use the md5sum.exe from
etree.org).

I really don't know if it's something going on while doing the backup or while
doing the restore :(       How would you troubleshoot this since there's no
backup verification process on NBU?

Thanks,
Jorge
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