Questions on weekly DRM setup

[jmolina07]

Hi there,

I've been searching on this forum and reading redbook sg246844 to learn and setup DRM on our TSM server, but i've still some doubts hopefully you can answer.

From what i can understand:

1. The rotation/expiration on DRM tapes will be exactly the same as in your primary pool, since files use Mgmtclass retention. That is, i cannot use a different rotation for my DRM than i use for my daily.

2. If i want to have daily database backup and weekly DRM tape rotation, every monday i'll get 7 database tapes (!!) no matter what i do, being my only choice lowering the drmdbbackupexpiredays


The thing is, we have daily backup, then copy to a copypool. We want to add DRM on a weekly basis, the usual standard "i backup my primary pool to drmpool (thankfully only one tape!), backup my database and take it out", and wait for a month until reuse those tapes again.

The problem is our retention policy in our primary pool is 15 days, and i dont quite grasp how to play with reusedelay (i'd guess 15 days more?), and database settings...

I was thinking that i could do only weekly db backup to tape and daily to HD, but i don't know if drbdbbackupexpiredays would rotate those backups (and i wouldn't be able to use del volhist weekly without affecting drm..)

Hope it makes any sense, and thanks in advance for the replies!

 

[sgabriel62]

Set your DRM module to return TSM DB tapes at the interval you wish to focus on.
You could also then create DBS or DB snapshots and place this under a different return policy using the appropriate del volhist type=dbs command and switches. This way for example, you can send the TDB DBs offsite and keep the snapshots onsite, keeping the snapshots on a shorter return schedule. Your reusedelay affects when media becomes available to TSM, you may have media coming back in a set schedule but TSM wont use them until the delay threshold has been met.
Hope this helps

 

[jmolina07]

You could also then create DBS or DB snapshots and place this under a different return policy using the appropriate del volhist type=dbs command and switches.
Hope this helps

Thanks a lot!
I completely forgot about db snapshots, in fact, now that you mentioned it, i've found the answer to my question here:
http://www-1.ibm.com/support/docview.wss?uid=swg27006949&aid=1

"
There are two types of database backups that are typically used for recovery; full database backups and snapshot backups. Full database backups are typically done on a daily basis after all copy storage pools have been updated and they are stored on-site.

Snapshot database backups are full database backups, but they do not reset the recovery log. Snapshot database backups are typically used for off-site disaster recovery purposes. They are made on a daily basis following production of a copy storage pool and are sent off-site with the rest of the daily tapes."


I'll use move drmedia source=dbs option, and dbbackupexpiredays to expire DB snapshots every 30 days (4 dbs rotation) and use volhist to expire DBB every 7 days. That would mess with dbbackupexpiredays, but since i won't send any dbb offsite, i think that should be fine.

About reusedelay, it's a pity that the tape will be marked to come back by the DRM, since as it's not going to be used, it would be better if it was kept offsite with the dbsnapshots for point-in-time recovery...

Thanks again!

 

[BBB]

Note that reuse delay only affects volumes that have become empty. So your offsite volumes that still have data on them will not be returned by DRM after 7 days. Its only when all the data on a tape expires, or reclamation reclaims the tape, that the reuse delay comes into play.

 

[jmolina07]

Note that reuse delay only affects volumes that have become empty. So your offsite volumes that still have data on them will not be returned by DRM after 7 days. Its only when all the data on a tape expires, or reclamation reclaims the tape, that the reuse delay comes into play.

Thanks for the reply

So, it's my understanding that, if i have data in a vol. that expires in 15 days (thus making it "empty"), and reusedelay=15 days, my volume will come back in 15 days (not 30), but will not be used since reusedelay kicks in.

Wouldn't be better if, even "empty" (not, if you restore an earlier DBSnapshot), it stayed offsite until reusedelay finished? is there any way to accomplish this?

 

[BBB]

Yes it would be better if it worked like you wanted to - and that is how it actually does work!!!

In 15 days it will become "pending" assuming it is completely empty. It will then spend another 15 days offsite in pending mode because of what you sent reuse delay to. Therefore it will return by DRM in 30 days total.

 

[jmolina07]

Yes it would be better if it worked like you wanted to - and that is how it actually does work!!!

Ah! That's great, thanks for the clarification. I guess I misunderstood reusedelay when I read about it elsewhere.

Thanks to everyone, you've been very helpful :up: