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Volume Shadow Copy - Corrupted Database Files


Cody Luera
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  • IPRO Employee

What is Volume Shadow Copy?

 

Microsoft's Volume Shadow Copy service (also known as VSS) is a useful tool built into Windows that allows a user to retrieve a previous version of a file in the event a file has been deleted or changed by mistake. Volume Shadow Copy creates a read-only 'Snapshot' of the volume of a drive (operates at the block level). Basically, it can 'track changes' on a drive volume.

 

 

How to find previous version created by Shadow Copy?

 

The snapshots, or 'Previous Versions', that are created can be accessed by finding the specific folder you want to check for, right-clicking the folder, and selecting 'Properties'. In the Properties screen, you will see 'Previous Versions' as a tab. In that tab, you will see the previous version of the folder and be able to open it to select certain files, or restore it.

 

[ATTACH=CONFIG]n2065[/ATTACH]

 

How can Volume Shadow Copy cause corruption of an Eclipse SE database?

 

Shadow Copy creates a 'Snapshot' of the volume, which is not on individual files, but rather the volume of the drive. In some instances, this process can cause a quick, temporary pause in disk activity. The problem occurs when Eclipse SE (either from Admin or Desktop) is trying to write data to the database files on disk and the writing process is interrupted. Once the interruption occurs, it can cause partial records to be written to the database files. When trying to access these files, users may encounter issues trying to login, open a database, or even index.

 

The only time we have seen this be an issue is during the scheduled Shadow Copy process. For instance, the scheduled time to run is 7:00 PM. A user starts a Native Ingestion, OCR, import, or index process at 6:50 PM and it run until 7:12 PM. The Shadow Copy will occur during the SE process, and cause the partial data write.

 

Ways to avoid/prevent this from happening?

 

As of now, our suggestion is to limit the Shadow Copy snapshot to occur during a non-busy time frame where users are not interacting with databases. For instance, at midnight or very early morning. If a large data writing process (Ingestion, OCR, etc.) is being ran overnight, it may be better to suspend Shadow Copy while the process executes.

 

Other Considerations:

 

Shadow Copy can also be used by other applications/backup programs. The interruption in writing data could be caused by another backup program.

 

Going forward:

 

Not often do we see this be an issue, however, I will continue to contribute to this post to determine different alternatives.

Edited by Cody Luera
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  • IPRO Employee

What is Volume Shadow Copy?

 

Microsoft's Volume Shadow Copy service (also known as VSS) is a useful tool built into Windows that allows a user to retrieve a previous version of a file in the event a file has been deleted or changed by mistake. Volume Shadow Copy creates a read-only 'Snapshot' of the volume of a drive (operates at the block level). Basically, it can 'track changes' on a drive volume.

 

 

How to find previous version created by Shadow Copy?

 

The snapshots, or 'Previous Versions', that are created can be accessed by finding the specific folder you want to check for, right-clicking the folder, and selecting 'Properties'. In the Properties screen, you will see 'Previous Versions' as a tab. In that tab, you will see the previous version of the folder and be able to open it to select certain files, or restore it.

 

Previous_Versions_Vista.png.e2822af883692dc8e4a456c9a67f9657.png

 

How can Volume Shadow Copy cause corruption of an Eclipse SE database?

 

Shadow Copy creates a 'Snapshot' of the volume, which is not on individual files, but rather the volume of the drive. In some instances, this process can cause a quick, temporary pause in disk activity. The problem occurs when Eclipse SE (either from Admin or Desktop) is trying to write data to the database files on disk and the writing process is interrupted. Once the interruption occurs, it can cause partial records to be written to the database files. When trying to access these files, users may encounter issues trying to login, open a database, or even index.

 

The only time we have seen this be an issue is during the scheduled Shadow Copy process. For instance, the scheduled time to run is 7:00 PM. A user starts a Native Ingestion, OCR, import, or index process at 6:50 PM and it run until 7:12 PM. The Shadow Copy will occur during the SE process, and cause the partial data write.

 

Ways to avoid/prevent this from happening?

 

As of now, our suggestion is to limit the Shadow Copy snapshot to occur during a non-busy time frame where users are not interacting with databases. For instance, at midnight or very early morning. If a large data writing process (Ingestion, OCR, etc.) is being ran overnight, it may be better to suspend Shadow Copy while the process executes.

 

Other Considerations:

 

Shadow Copy can also be used by other applications/backup programs. The interruption in writing data could be caused by another backup program.

 

Going forward:

 

Not often do we see this be an issue, however, I will continue to contribute to this post to determine different alternatives.

Edited by Cody Luera
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