NTBackup verify fails over network from Server 2003 R2

I have a Windows Server 2003 R2 box, used as a file server, and backup DNS server for our domain. I use BackupAssist to schedule NTBackup to do weekly full backups and daily differentials. The backups are stored on a SATA hard drive in a removable tray on a Windows 7 (64 bit) PC on the same LAN.

Starting a couple months ago, the full backups fail to verify very close to the end. For a while, if I re-ran the full backup manually the following day, it would succeed with no issues. Now they fail 100% consistently either scheduled or manual. The smaller daily backups always succeed.

I have updated the NIC drivers on the server, and tested using only a single NIC. I disabled all of the advanced options on the NICs. I have swapped to a different drive tray, which was confirmed good hardware by SpinRite the night before I brought it in. None of these made any difference.

The only successful full backup I've done has been to a USB drive attached directly to the server.

Have I missed something stupid?
localmagicAsked:
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localmagicConnect With a Mentor Author Commented:
I opened an incident with Microsoft about this, and was told that verify is known not to work in some instances, and they recommended that I disable verification in this case. ("Doc, it hurts when I do this!" "Don't do that!")

Also, apparently NTBackup's verify is simply examining checksums stored in the .bkf file that were created while backing up, it does *not* compare to the files that were backed up.

Hopefully this will save somebody else the trouble in the future!
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Chris StauntonCommented:
backup drive is formatted NTFS?  A lot of times removable drives are formatted FAT32 and this causes problems with larger size files....

Just a thought


Shooter
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thoughtlessmindCommented:
I had a similar issue and ended up having to turn off shadow copy on the drive the back up was being saved to. I again had a similar issue when a tech defraged the back up drive. I ended up having to delete the back files as the issue seemed to be with rewriting over the defraged back up files. Once it was just writing a new file opposed to writing over the old file it worked. see if either of these help you

Thoughtlessmind
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localmagicAuthor Commented:
Shooter: It is an NTFS volume, i should have mentioned that before! The full backups are running about 120GB lately.

Thoughtlessmind: I just checked, and shadow copies were already off for the tray. However, Win7's auto-defrag was enabled for that drive. I've disabled that, deleted a full backup and started it running a new one into the same slot. I'll have an update in a couple hours!
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Chris StauntonCommented:
I've had verify and Write Caching errors before on NT Backup that were fixed by a format of the external drive as well, hope thoughtlessmind's solution works for you!

Shooter
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localmagicAuthor Commented:
The following tests have now also failed (in this order):

* Disable auto-defrag, delete a backup, run a new backup to the same filename (which now creates a new file instead of overwriting).
* Swap to a brand-new drive (scheduled to be added to rotation in a week, I did it early for testing). This drive has never had any data on it, it was formatted and installed. VSS and auto-defrag still disabled (and will stay that way...).
* On the new drive, disable write caching, delete previous test file, backup again.

I'm quite thoroughly stumped at this point!
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thoughtlessmindCommented:
is it giving you an error message when the back up fails to verify and if so can you post it?
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localmagicAuthor Commented:
Here are the relevant items from the server's event logs, the NTBackup log, and the log from BackupAssist. The script section in the BackupAssist log is part of a Microsoft recommended tweak to speed up NTBackup (They use it for exchange clusters, but it works anywhere, see http://technet.microsoft.com/en-us/library/bb735157.aspx for details).

The Win7 box that is the destination of this backup never logs anything during the relevant time window, or if it does, I haven't found it yet!
eventlog.txt
ntbackup-log.txt
BackupAssist-log.txt
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