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Home > Archive > Backup Software > March 2006 > MS Backup and post restore verification
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MS Backup and post restore verification
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| tstoneman4@hotmail.com 2006-03-14, 2:46 am |
| Hi all,
I just restored a Microsoft backup file (from Windows 2003 server) I
had. When I did the backup, I used the verify option, however, while
doing the restore, there was no verify option available.
Is there a way I can check to make sure that the files that were
restored were not somehow corrupted, maybe due to a physical disk
problem, etc? Is there a utility that Windows has that does this on a
folder basis?
Thanks
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| DevDude 2006-03-15, 2:46 am |
| The windows backup program does not provide a verify on restore feature. If
the file was backed up successfully, then the windows programming API's
should get a failure when streaming the file back to the disk. If they
receive a failure, then you would know that the file was not restored
successfully. There is room for error, but much smaller room than on the
backup. If you got it restored successfully, you should be fine. If there is
a known problem with restore, a patch would be produced.
Nick
<tstoneman4@hotmail.com> wrote in message
news:1142320250.468114.285170@z34g2000cwc.googlegroups.com...
> Hi all,
>
> I just restored a Microsoft backup file (from Windows 2003 server) I
> had. When I did the backup, I used the verify option, however, while
> doing the restore, there was no verify option available.
>
> Is there a way I can check to make sure that the files that were
> restored were not somehow corrupted, maybe due to a physical disk
> problem, etc? Is there a utility that Windows has that does this on a
> folder basis?
>
> Thanks
>
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| tstoneman4@hotmail.com 2006-03-21, 2:55 am |
| FYI I did the restore, and then ran a byte-by-byte analysis on each
file overnight using a commercial product that we had in-house.
As an aside, I did some research and it turns out that the verify
command on xcopy does not actually verify that the files are the same,
it just verifies that the file was created properly,.
After doing a restore of 150 GB, and doing a byte-by-byte analysis, it
turns out that I had 12 files that had a few bytes off. Scary in that
you can have byte errors propogated without even knowing it, and kind
of calls into question the accuracy of restores. I'm sure the accuracy
is over 99.9999%, but in this age of file CRCs, MD5 hashes, etc, you
would think that the copy would be 100%.
DevDude wrote:[vbcol=seagreen]
> The windows backup program does not provide a verify on restore feature. If
> the file was backed up successfully, then the windows programming API's
> should get a failure when streaming the file back to the disk. If they
> receive a failure, then you would know that the file was not restored
> successfully. There is room for error, but much smaller room than on the
> backup. If you got it restored successfully, you should be fine. If there is
> a known problem with restore, a patch would be produced.
>
> Nick
>
>
>
> <tstoneman4@hotmail.com> wrote in message
> news:1142320250.468114.285170@z34g2000cwc.googlegroups.com...
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| J. Yazel 2006-03-21, 2:55 am |
| >
>After doing a restore of 150 GB, and doing a byte-by-byte analysis, it
>turns out that I had 12 files that had a few bytes off. Scary in that
>you can have byte errors propogated without even knowing it, and kind
>of calls into question the accuracy of restores. I'm sure the accuracy
>is over 99.9999%, but in this age of file CRCs, MD5 hashes, etc, you
>would think that the copy would be 100%.
> ====================
Good backup/restore programs have always verified byte/for/byte
both on the backup phase and the restore phase (at least for the
40 years that I have been in computers).
Are you surprised that MS software doesn't do what almost everybody
thinks it does?
Jack
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