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I'm facing this problem: on Windows 2003 server STD, I can't safely perform unattended data backup on tape (HP LTO-1 drive) because it asks for a free media tape after 90GB of data written. The hardware compression is enabled, so I expect to back-up a minimum of 100GB of data. But the backup stops before the nominal tape capacity, while some week ago I was able to backup 148GB of data. For example, last wednesday:

Backup started on 14/03/2012 at 23.07.
The requested media failed to mount. The operation was aborted.
The operation was ended.
Backup completed on 15/03/2012 at 3.59.
Directories: 12393
Files: 182764
Bytes: 96.219.704.680
Time: 4 hours, 51 minutes, and 44 seconds

We have 130 tapes, the older is from 2005, the newest is from nov. 2011. Each tape written it's stowed in a cabinet for 14 months, after this period is rewritten (we make 2 full backups a week).

In Event Viewer there is only error 8019:

Event Type: Error
Event Source: NTBackup
Event Category: None
Event ID: 8019
Date: 15/03/2012
Time: 3.59.01
User: N/A
Computer: W3KSRV01
End Operation: Warnings or errors were encountered.
Consult the backup report for more details.

Where should I investigate? This afternoon I have to patch the server (monthly fix) and of course reboot...

Update: from "Computer Management" I can't free a tape (the option is grayed). But from ntbackup I can free it. I think that something hanged in the system...

Update2: after the reboot, the nightly backup went OK: 98GB+System State. Let's wait some time to see if the problem is gone away...

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up vote 0 down vote accepted

Some thoughts:

  • If the media is old, maybe the drive has to skip some sectors because it can't reliable read the data after the write (LTO always does a verify-after-write). Try a new tape and see if you can store more data on it.
  • This shouldn't be a problem if you backup your OS, but if you backup only pre-compressed files (archives, JPGs, MP3 etc)., it might be that activating hardware compression actually increases the backup size.
share|improve this answer
At least one media was "new", i.e. used for the second time The type of data is a mix of DTP files (pdf, ai, indd, jpg, tiff, eps) and aother files, from the beginning. We never had a trouble until the total size was under 110GB. – AndrewQ Mar 16 '12 at 11:12

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