LTO tapes - 20 TB maximum capacity

  • 25 October 2023
  • 3 replies


There is a new physical tape library configured in this environment (HPE MSL G3 2024) with 2 tape HPE Ultrium 8-SCSI FC drives. 

The tape library was added in Commvault and few auxiliary copy jobs performed:

1. With the hardware compression disabled in Commvault storage policy copy data path configuration. The size of data on the first tapes was 10 TB.

2. With the hardware compression enabledin Commvault storage policy copy data path configuration. The size of data on each tapes was 20-21 TB.

The backup data type is VMware backups.

Our question is why Commvault is not placing more than 30 TB on each tape, considering they are LTO8 and hardware compression is enabled? 

This customer has another Commvault environment  , with similar backup devices and same settings, they are able to accommodate between 30 -40 TB.

3 replies

Badge +3

Hi @Sunil R ,

Good day.

The eighth generation of LTO Ultrium tape media delivers 12 TB native capacity and up to 30 TB of compressed capacity for even greater efficiency and performance.

Even after enabling the hardware compression if the media is not able to accommodate more data means, as a first phase I would like you to get in touch with the hardware vendor.




Userlevel 7
Badge +19

 @Sunil R are you also creating backups directly to tape media? In cases where you aux-copy the data to tape media you will see that the amount of data that is written to tape is almost equal to the amount of data that the tape can hold in uncompressed state. This is because Commvault by default preforms software compression. 

See also:

Badge +1

Hello @Onno van den Berg ,


thanks for the article. That is declare, why we See only native capacity on my LTO9 tapes. The library is direct connected via SAS on Media Agent.

But we use software encryption on all external media. But this will eleminate the feature hardware compression.


With best regards,