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Duplication bug patch


Anthony
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There is a duplication bug in the current release (aka v2.3.9.0) that can cause the a mismatch time stamp between the primary and duplicate files when there is a daylight saving's time shift. This can cause some files to be unnecessary re-duplicated. If you are seeing re-duplication for no obvious reason, I recommend installing the attached patch.

 

Important, you must be on the latest release v2.3.9.0 before applying this patch.

 

To install :- 
1) Open task manager and kill task "DriveBenderService.exe" (make sure the pool is not busy copying files etc). 
2) Unzip the attached files to the Drive Bender folder (typically "C:\Program Files\Division-M\Drive Bender"), overwriting the existing file. 
3) Reboot.
 
As a side note, we are seeing some users experience performance issues when they have enabled CRC validation (this is made worse by the bug mentioned above). While we have not been able to replicate this, we are recommending users disable this feature as it does not offer any real benefit. For further details, please see - http://divisionm.zendesk.com/entries/107477866-What-is-CRC-validation-and-should-I-be-using-it-

DriveBenderService_2395.zip

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  • 4 weeks later...

Why does CRC validation not offer any real benefit?  The documentation for Drive Bender says otherwise:

 

Safety
  • Enable CRC file validation: Enabling CRC file validation provide an added degree of security by ensuring events (such as physical drive issues) do no corrupt or modify any duplicated file. Important - Disabling this option means that files are validated by file size and time stamp only. Having this option enabled ensures any duplicated files validated against the original is done using a CRC value, however this can impact the time required to validate a file.
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First up sorry for the late reply... it has been a busy period.

 

Hi,

 

thanks for this fast responce! the patch seems to work. will there be the same Problem when the change winter/summer-time will be next year?

 

markus

 

No, this patch fixes the issue.

 

Hi Anthony,

Is this patch compatible with the 2.3.9.4 beta I have been running. I noticed it does not included the driver update. Are you still planning to have a "final" release including the existing fixes?

 

Cheers

 

Yes... the updated driver will be shipped in the next update which is soon to be released, however the driver you are running is compatible.

 

 

Why does CRC validation not offer any real benefit?  The documentation for Drive Bender says otherwise:

 

Safety
  • Enable CRC file validation: Enabling CRC file validation provide an added degree of security by ensuring events (such as physical drive issues) do no corrupt or modify any duplicated file. Important - Disabling this option means that files are validated by file size and time stamp only. Having this option enabled ensures any duplicated files validated against the original is done using a CRC value, however this can impact the time required to validate a file.

 

 

This text was written during the original development... my guess is that it was written to meet the UI that was in place at the time (it was a long time ago). I can tell you that it's original intent was more to do with development and the assurance that the code we were writing was doing as intended (aka duplicated files were duplicating / balancing without error). When coping files from one drive to another, any errors will happen at the hardware level (hard drive, SATA interface or connectors etc), and because we do not track a primary file's CRC, a mismatched CRC is difficult to diagnose. For example, was the CRC error induced during the CRC calculation on the primary file etc? I want to remove the feature for this reason, and the fact that we get many CRC performance related issues via support. A couple of years ago I did remove it from a beta release but received complaints so it was reimplemented. Having sad all that, I'm happy to hear from users on the subject.

 

I did not get that comment either. Date time stamps do not validate the content but CRC does and I find that important.

 

We rely on NTFS here (which is a well proven file system)... and remember that all duplicates are written and modified in real time along with the primary... so the time stamps should always be in sync. Could a primary be changed and the duplicate not? Yes if the user was accessing a drive directly, however the time stamp would reflect this and the file system health check would catch this.

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  • 2 weeks later...

I applied this patch and everything seems to work fine except I can no longer manage file/folder security.

The tab is not there at any level in the folder structure.

 

I'll post a log if you think it would help, but I had to revert it for now to manage security.

 

If you look at the format type, is it list as NTFS?
I have done some checking here and there is no issue. And given the changing in the patch, I would not expect the patch to cause such a problem. After you reverted back to v2.3.9.0, is the issue resolved?
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Sorry for the delay..

I finally had a chance to re-apply this patch.

After killing the service, replacing the file, and rebooting, I again do not have a security tab on the pool drive.

 

 

 

Without the patch, I see files getting their timestamp changed 1 hour when removing a drive. Would this be the same bug this patch is for?

 

 

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