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Certain tapes not written to after initial writing and before appendable date setting

  • 14 December 2021
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In my organization, I have two HP MSL4048 tape libraries containing two Ultrium drives which uses LTO7 tapes with a capacity of 5.47 TB. The firmware for both libraries are the same. The Use Appendable media setting is 14 days.

For the two years, for one of the tape libraries, about once every two months one of the empty tapes gets written to but it doesn’t fill up to the capacity. And if in three days the tape is not written to, then it will not be written to at all and will choose a different tape, even though it’s before the appendable setting of 14 days, and its media info properties clearly states Yes of it’s appendable. The other tape library on the other hand will always fill tapes to its capacity.

Attached file no_writing_prematurely.jpg shows such an example. The last time it was written to was on 12/6/21, and the tape is not full and there’s 7 more days to be appendable. But it will not be written to at all. As mentioned, this occurs about once a month with a random tape. I wonder if there’s additional settings that I should be aware about.

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Best answer by JSNOPUD 14 December 2021, 18:32

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Hi @JSNOPUD , thanks for the post and the INCREDIBLY detailed screenshot!

Appendable tapes should be used first as they are used in the order of Appendable, Aged, then Spare.

Can you take a look at the Spare Media Pool properties for this tape and see how media is set to be selected?

https://documentation.commvault.com/11.24/expert/58040_spare_group_properties_general.html

Spare/Cleaning Media Selection Criteria

  • Use most reused media first

    Specifies that the most recycled media is used first when a job requires a media, and that there is recycled media available in the scratch pool.

  • Use least reused media first

    Specifies that the least recycled media or new media is used first when a job requires a media, and that there is new media is available in the scratch pool.

  • Use media based on capacity

    Specifies whether you want to use and fill the lower capacity media first or the higher capacity media first.

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@Mike Struening For the Default Scratch settings for this Media Group in my tape library, they are set as High Priority and for the Spare Media Selection Criteria, it’s set as Use lease reused Media first.

 

What is really strange now is that when I checked this morning, the particular tape that I was complaining about is now being written to. 

 

I guess for now, this issue can be closed.

Userlevel 7
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If you watch it, it will behave :joy:

If it acts up again, reply here and I’ll unmark the answer.

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