[Info-vax] Backup verify problems

[Bob Gezelter]

On Jan 30, 6:26 pm, gsdguy <peter... at chem.washington.edu> wrote:
> I am getting backup verify errors and I don’t know why. I hope someone
> can explain what is happening.
>
> I had a disk and tape drive failure and restore the disk from a backup
> tape ( I bought a new DAT tape drive). I decided to start using the /
> verify switch when I do backups. When I did my first backup to tape
> with /verify I got verify errors like the ones shown below.
>
> %BACKUP-E-VERIFYERR, verification error for block 31 of DUA2:[LEROY]
> MAIL.MAI;1
> %BACKUP-E-VERIFYERR, verification error for block 32 of DUA2:[LEROY]
> MAIL.MAI;1
> %BACKUP-E-VERIFYERR, verification error for block 33 of DUA2:[LEROY]
> MAIL.MAI;1
> %BACKUP-E-VERIFYERR, verification error for block 34 of DUA2:[LEROY]
> MAIL.MAI;1
> %BACKUP-E-VERIFYERR, verification error for block 35 of DUA2:[LEROY]
> MAIL.MAI;1
> %BACKUP-E-VERIFYERR, verification error for block 36 of DUA2:[LEROY]
> MAIL.MAI;1
>
> I created a disk backup saveset and got the same verify errors. I
> checked the error log for any hardware errors and there were no
> errors. I then restored one of the files that had verify errors to
> another disk and did a difference between the original file and the
> restored file. The difference program said that there was no
> difference between the two files. I also did an analyze/disk on the
> disk drive and there are not errors.
>
> Can someone explain what is going on? How can I get rid of these
> verify errors? Thank you.

gsdguy,

Were there mail messages processed (delivered, deleted, sent) during
the time that the BACKUP was running.

Verification errors will happen both for hardware problems AND when
the contents of the file changes in any way between the time that the
file was copied to the saveset during the first pass and when it was
verified during the second pass.

Depending upon the situation, it may be feasible to shutdown mail
delivery during backup operations. In general, for VERIFY to work, a
quiescent volume is needed. Otherwise, some number of files will have
their contents changed between passes.

- Bob Gezelter, http://www.rlgsc.com