Does CTA know the matrix of media/drive compatibility?

Looking at Enstore’s metadata, all the tapes of certain media formats are stored in a single logical library and associated with drives that can read those media.

Is that necessary in CTA or does CTA know that an LTO7M tape can only go into an LTO8 drive, etc.

Hi Eric,

similar logic is necessary in CTA as well. For example LTO7M tape cartridges:

pcvlado ~ > cta-admin mt ls|egrep "LTO7M|media"
media type cartridge       capacity primary density code secondary density code number of wraps min LPos max LPos c.user                   c.time m.user                   m.time comment
     LTO7M     LTO-7  9000000000000                   93                      0             168     2696   171097 mdavis           ctadevmichael 2020-06-22 16:54  vlado ctaproductionfrontend01 2020-11-02 19:39 LTO-7 M8 cartridge formated at 9 TB

are defined in IBM1L8 logical tape library which contains only LTO8 tape drives:

pcvlado ~ > cta-admin tape ls --mt LTO7M|egrep "LTO7M|vid"
   vid media type       vendor library order        tapepool            vo encryption key name capacity occupancy last fseq  full from castor    state         state reason label drive       label time last w drive      last w time w mounts last r drive      last r time r mounts c.user                   c.time     m.user                   m.time comment                                                                            
L70001      LTO7M IBM-FUJIFILM  IBM1L8     -     r_atlas_raw         ATLAS                   -     9.0T      9.0T      5148  true        true   ACTIVE                    -      CASTOR 1970-01-01 01:00     tpsrv229 2018-11-23 05:51        1     I1L80933 2023-08-09 09:42       23 CASTOR                  CASTOR 2020-06-23 20:01 tape-local ctaproductionfrontend02 2023-08-09 12:00 -                                                                                  
L70005      LTO7M IBM-FUJIFILM  IBM1L8     -       r_cms_fam           CMS                   -     9.0T      8.9T      3500  true        true   ACTIVE                    -      CASTOR 1970-01-01 01:00     tpsrv465 2018-08-04 19:14        2     I1L80914 2023-10-29 17:48      188 CASTOR                  CASTOR 2020-11-30 19:58 tape-local ctaproductionfrontend02 2023-04-21 12:00 -                                                                                  

This allows for detailed control which tapes are utilized by which drives.

Sometimes, when you introduce new generation of tape drives, there is not a lot of read workload to do. You can temporarily move some older tapes (e.g. LTO8 tapes to a logical library with LTO9 drives) so the new drives are busy. As you fill the new tapes, then the new drives are more and more busy so you can move the old tapes back to the previous logical library.

Let me know if you have further questions.

Vladimir Bahyl

A drive will try to mount and read all tapes from its logical tape library, so it is up to operators to define this association as Vladimir explained this.

I opened a ticket some time ago to relax this situation for tape drives that can read multiple tape mediatypes: Deal with tape drives that can read multiple media types (#1) · Issues · cta / CTA · GitLab

If you want to implement this feature, there are more details in the ticket and we can continue the discussion there.