topic Re: Verify Backup in Operating System - HP-UX

Verify Backup

Jose Gallegos_1 — Thu, 04 Nov 1999 12:47:50 GMT

What is the best way to verify a fbackup's integrity. Is there a verify routine
that can be run?

Re: Verify Backup

Jason Luginbuhl_1 — Thu, 04 Nov 1999 13:27:52 GMT

Jose,

Unfortunately there is no real way to know for sure that a backup is good until
you attempt to restore it. Many customers choose to verify their backups are
good by restoring a random file from the tape from their periodic backups. This
is a pretty good indicator that the backup is good. I have seen that other
customers choose to do an frecover -I to pull the index from the tape. This
will check that the index is intact and does again point to a good backup, but
it is not a guarantee that all of the data is good.

Re: Verify Backup

Vitek Pepas_1 — Thu, 04 Nov 1999 14:10:32 GMT

Try 'frecover -xN'. It reads the backup without restoring data - see frecover
man page for details.

Re: Verify Backup

Paul Winchcombe_1 — Fri, 05 Nov 1999 03:49:07 GMT

This is a procedure I use to use at HP-UX 9.04

I use to create a file in root called /zzz. As fbackup does backups in
alphbetical order /zzz should be the last file on backup.

My verify routine was then to recover this file.

Regards

Paul

Re: Verify Backup

Jason Luginbuhl_1 — Fri, 05 Nov 1999 06:30:33 GMT

Good suggestions from Paul and Vitek. Vitek pointed out an option that I was
unaware of. He pointed out the -N option of frecover for verifying a backup.
Here is the documentation from the manpage:

-N
(no recovery) Prevent frecover from actually recovering
any files onto disk, but read the backup as if it was,
in fact, recovering the data from the backup, producing
the same output that it would on a normal recovery.
This option is useful for verifying backup media contents in terms of validity
(block checksum errors
are reported), and contents (a listing of files can be
produced by using the -N and -v options together).
Note that the listing of files produced with the -N and
-v options requires the reading of the entire backup,
but is therefore a more accurate reflection of the
backup's contents than the index stored at the
beginning of the backup (which was created at the start
of the backup session, and is not changed during the
course of the backup).

Re: Verify Backup

Robert Gamble_3 — Thu, 11 Nov 1999 05:36:14 GMT

That is the same procedure I use!
I have been using /var/yp/zxz on all my systems as my 'reference file' to do
random audits of my backups.

My procedure displays the Volume Header to screen, then cp the Index to an
audit directory then restores the file at the end of the volume and does a
checksum against the original 'zxz'. It is the best way to verify a good backup
that our team could think of using fbackup/frecover.