Tape Backup: understanding media sets

M

marte

Active Member
Jun 28, 2019
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I think I have a misunderstanding concerning media sets when using a tape library.

I have configured a media pool with a allocation policy "monthly" and a retention policy "2 weeks".

My understanding was, when removing the tape the backups are on from the library, a new tape gets selected with starts a new media set (thus, with a full backup), as the ols one can't be continued.

first backup works as expected (full backup):

Code: 
Duration: 2h 14min 49s

Used Tapes:
KH3912L6

the second also (changes):

Code: 
Duration: 6min 54s

Used Tapes:
KH3912L6

But, after removing the tape, I expected another full backup, but got:

Code: 
Duration: 4min 20s

Used Tapes:
KH3913L6

So, only changes were written (at least thats what I think looking at the duration and how it gets displayed):
1705928510937.png

Why was no new media set started? In the documentation is written

Additionally, the following events may allocate a new media set:
  • Required tape is offline (and you use a tape library).

Okay, it MAY start a new media set. Why it doesn't in my case?
 
Hi

just fyi, i did not forget this thread :) honestly i'm not sure why it did not allocate a new media-set, but could you post your allocation/retention policy of that pool, then i can look into the source and see what might be going on there
(also maybe the docs are inaccurate or theres some info there missing)

EDIT: oops, i overlooked you already posted the policies... i'll look as soon as i have some time
 
Last edited:
dcsapak said:
Hi

just fyi, i did not forget this thread :) honestly i'm not sure why it did not allocate a new media-set, but could you post your allocation/retention policy of that pool, then i can look into the source and see what might be going on there
(also maybe the docs are inaccurate or theres some info there missing)

EDIT: oops, i overlooked you already posted the policies... i'll look as soon as i have some time
Click to expand...
thank you!

I had already labeled some tapes for this pool, so that I can be sure which tapes can be used:
1706171826447.png
Is this maybe a problem?

Thank you & best regards
 
ok looking at the code, there are a few reasons when a new media set is created:

* if it's forced (via 'new backup' in the gui for example)
* because of the policy ( always or the time matches)
* an error with the media set happened ( e.g. missing tapes in the inventory, owner error etc. )
* the pool encryption key changed
* or if the last writable media is "vaulted" ( so marked as being in a vault)
(also maybe some reason that i missed)

though i'm questioning the last part a bit, as it does not make complete sense to me that only in the case of vaulted tapes a new media set is created.
i have to confer with my colleague though, maybe there is a deeper reason for this that i'm currently not seeing
 
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