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.host c.time m.user m.host 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.host c.time m.user m.host 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.
Julien