Error 126 and 16 DPX 5

[agrigera]

DPX 5 was working fine for several months and now is showing error 126 and some 16 in the daily jobs (not always) most of the times is in the verification process. After the error showed up I run again the verification process and everything is fine.

I'm running Win Server 2008 Enterprise 32bits with a Tape library MSL4048 and 2x LTO 4 FC drives.

Have the latest firmware for library and drives and the last DPX 5.0.01 patch applied.

Any idea how to fix this?

Thanks

[agrigera]

OK I'm going to answer myself in case anyone can use the info.

I'm still testing the solution but at least I understand what the problem is.

Every time DP runs a Copy task by default generates an "Snapshot" inside the volumen in wich the files are located. This snapshot is controlled by a Microsoft Service by the name of Volsnap.sys (VSS)

Now so far so good, DP use this snapshot as a photo of what the volumen looks like when you start to run the task. During the task execution DP checks this snapshot to know exactly wich files to backup and wich not. When the errors occur was because for some reason Windows decided to remove the snapshot for the Volume in question (in my case D:) and you can see an Event ID 25 in the System log.

The reason that Windows decided to destroy the snapshots for the volume is because the "shadow copy" could not grow any more. This is because when the service runs the snapshot, every change in the volume (adding files for example) is saved in an image called Shadow Copy in a hidden folder in the same Volumen and of course that image has by default a Maximun value wich in my case is the 10% of the volumen size.

Like I said I'm testing 1 of the 2 possible solutions to this problem, wich never manifest itself in the past since the volumen of data I was moving was not big enough to fill the image.

The first solution is to increase the size limit of the shadow image in the volume wich can be done in Win Server 2008 in the properties of the volume, you can set a bigger limit or just select unlimited.

This solution of course depends on the size of the volumen and the free space you have wich in my case is not that big anymore so I went for the second solution wich is to deactivate the snapshot creation in DPX. You can uncheck in every copy task in the Advanced/Options section the option to "activate Snapshots".

What I'm testing right now is the stability of the copy task and what it does with the files I'm sending to the system while the task is running.

I'll get back to you whit the results.

Best regards

[Rajanikant]

Hi Agrigera,

thanks for the detailed explanation of the errors and the testing done. I am trying to add some more for the solution

Detailed explanation of the errors reported:

Error: 16 SBERR_FILE_NOT_FOUND :

File not found when attempting to open a file, the IO manager could not open the requested file. The file is probably missing or currently in use (unlikely). Retry the operation again. If the problem persists, try to repair the database or restore from a tape which contains a backup of the database.

Error: 126 SBERR_PATH_NOT_FOUND :

Path not found when attempting to access a file path, the IO manager could not find the requested file system path. The path is probably missing or currently in use. Retry the operation again. If the problem persists, try to repair the catalog or restore from a media which contains a backup of the catalog.

Backup logs give message similar to below:

As you have mentioned, these errors are dependent on the VSS snapshot. The simplest way to fix these issues is to have a larger snapshot size and good enough free space on each volume you are backing up for the open file management of the application.

If there are issues with free space availability on the volume, the other work around is to make sure the files are closed when the backups are scheduled. If there are any database that is backed up apart from MS SQL or Exchange, the application should be stopped to make the flat file backup of the database

Hope this helps !!!