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Question

Unable to Reuse LTO-6 Tape After Backup

  • July 4, 2026
  • 1 reply
  • 30 views

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Hi everyone,

I'm looking for some advice regarding a tape backup issue in Commvault.

Environment:

    Commvault Web Console v11.40.42
    HPE Ultrium LTO-6 standalone tape drive

This tape drive was previously used in another backup solution. Before using it with Commvault, I:

    Stamped the tape media.
    Used the Delete and Reuse option to erase the existing contents.
    Set the tape as Primary media.
    Started a backup job.

The first backup completes successfully and writes about 1.16 TB of data. However, after the backup finishes, the tape media is usually marked as Unavailable, and sometimes it is marked as Full.

From my understanding, an LTO-6 tape should have a native capacity of around 2.5 TB, so I'm not sure why Commvault considers the tape full after only about 1.16 TB of backup data.

When I start another backup job, Commvault prompts me to insert a new tape instead of continuing to write to the current tape.

I also noticed the following:

    If I power cycle the tape drive, the tape appears as Active again in the Media tab.
    However, the backup still cannot continue because Commvault displays an "Insert New Media" alert.
    I searched for the Start New Media option mentioned in some documentation, but I cannot find it in the Web Console.

My main questions are:

    Why is the tape media being marked as Unavailable most of the time after the first backup?
    Why is Commvault treating the tape as Full after only about 1.16 TB when an LTO-6 tape should be able to store much more?
    Why is Commvault requesting a new tape when the current tape appears to have remaining capacity?
    Is there a media or storage policy setting that determines when Commvault switches to a new tape?


Has anyone experienced this issue before?

Could this be related to:

    Media policy or storage policy configuration?
    Scratch pool or tape media settings?
    Tape stamping or formatting?
    LTO-6 drive firmware?
    A limitation or difference in the Web Console (v11.40.42)?

Any suggestions on what I should check or how to troubleshoot this issue would be greatly appreciated.

Thank you!

1 reply

Paul G
Explorer
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  • Explorer
  • July 6, 2026

Hi ​@Thet Paing,

Commvault has the option to mark the media as full after a backup or auxilliary copy has completed succesfully, even when there is stil storage left on the tape. You should check your job settings to see if it does so. A tape that is marked as full cannot be written to, even if there is still storage available on media. All data on the tape needs to be aged before you can reuse it.

Another reason why you cannot write to the same tape could be that they use diferent storage policies/plans. Commvault does not allow you to write differen storage policies/plans to the same tape unless you use a global tape copy as the basis for the tape copy.

 If these comments do not answer your question, please supply additional information to better identify your issue.

  • Is this a backup directly to tape?
  • Is the tape library used by multiple storage policies/plans?

Kind regards,

Paul G