V-79-57344-38721 - Failed to mount one or more virtual disk images

[porterville]

My previous question was locked for some reason, so I will ask again.

Has anyone experienced the V-79-57344-38721 - Failed to mount one or more virtual disk images error while doing a Forever Incremental backup to a Software-based Veritas Deduplication Storage?

I was experiencing this issue with a Windows 2012 R2 server earlier in the year. Veritas support tried a bunch of things for 3-4 months, but they could not fix it. I eventually had to change the backup method to an Agent Backup.

Now I am experiencing it with another server that was Windows 2012. I have upgraded the server to Windows 2016, but it is still causing the same issue.

The backup job is a Forever Incremental, and it seems to be related to the GRT. It has three sub-jobs. They are an Active Full, Consolidate Full, and a Forever Incremental. We are also using the veritas software deduplication storage. It is only successful for the Active Full backup, but not the Consolidate Full and Forever Incremental.

This same job is also backing up another server roughly the same size (~1TB), but it is running Windows 2012 R2. It completes successfully in all stages including the GRT.

There are also other jobs running Forever Incremental configured the same way, but they have smaller-sized Virtual Disks, and they complete successfully.

Things that I have tried that I can remember on the server earlier in the year:

• Updated Backupexec to the latest version (Did not help)
• Replaced the VirtFile driver (Did not help)
• Recreated the job (Did not help)
• Created a new Veritas Backupexec server. Then created the job using an alternate dedupe storage (Did not help)
• Backed up to another non-dedupe storage (This worked correctly), but we can't use non-dedupe storage for >1TB Virtual Disks.

[porterville · Accepted solution]

Hello All,

For those that are experiencing this issue, I wanted to share my work around for this problem.

Possible Cause

From what I could tell, there may be a timeout issue during the GRT stage using a deduplication storage.

Solution

I have the job setup as a Forever Incremental with two stages.

Stage 1: Has the following sub-jobs that backup to a non-dedupe storage temporarily

1. Active FULL, two-weeks, non-dedupe-storage
2. Consolidated FULL, two-weeks, non-dedupe-storage
3. Forever Incremental, two-weeks, non-dedupe-storage

Stage 2: Has the following three sub-jobs backup to the dedupe storage, immediately after each previous job

1. Duplicate Active FULL, one-year, dedupe-storage
2. Duplicate Consolidated FULL, one-year, dedupe-storage
3. Duplicate Forever Incremental, one-year, dedupe-storage

Results

• GRT is completed successfully for both temporary backup-set and duplicated backup-set