Question on Vary and access=readonly

[sariwat1]

We created a few disk pool volumes for a storage pool because the old disk pool volumes are going to be retired. The storage is being moved to another location so the new pools is on another storage device. We have set the old volumes to read-only so the new data will go to the new disk volumes that were just created.

Question1:
With the old disk vols in readonly mode, will migration recognize that the the pool size was reduced in half since half of the disk volumes are set to read only and adjust accordingly?

If migration is set at 60 hi 30 lo but the pool will only fill up to 50%, theoretically it should error out.

Question2:
If we vary off the read only disk volumes, is there any harm to the data currently on those volumes and will the size available to the stgpool be reflected?

Thanks,

Ben

P.S. We set the migration threshold lower to compensate but it would be nice to know the answer to those two questions.

 

[ALT-G]

We created a few disk pool volumes for a storage pool because the old disk pool volumes are going to be retired. The storage is being moved to another location so the new pools is on another storage device. We have set the old volumes to read-only so the new data will go to the new disk volumes that were just created.

Question1:
With the old disk vols in readonly mode, will migration recognize that the the pool size was reduced in half since half of the disk volumes are set to read only and adjust accordingly?

If migration is set at 60 hi 30 lo but the pool will only fill up to 50%, theoretically it should error out.

Question2:
If we vary off the read only disk volumes, is there any harm to the data currently on those volumes and will the size available to the stgpool be reflected?

Thanks,

Ben

P.S. We set the migration threshold lower to compensate but it would be nice to know the answer to those two questions.

Ben,
Question 1: Changes in access status to a volume has no bearing on the size of the storage pool, it only affects accessability to the volume. Set to read-only will allow all read functions to continue, just no further writing will be permitted.
Question 2: Varying the volumes to read only, or changing their access to any status will not affect the data on the volume.

Suggestion: IMHO, If you have added additional volumes to the disk pool you have two options; 1) Migrate the data to another storage pool lower in the storage hierarchy, then delete them. If they are cached sick pools you will neeed to specify the discard data option. 2) perform a "move data" command on the volumes you would like to retire, then delete them as outlined above.

Hope this helps...

~Rick

 

[sariwat1]

Hi ALT,

Thanks for the reply. My main concern is when you do a q stg, you get the total storage available in the pool. If you add new disk volumes to the disk storage pool, the percent available will increase even though there are read only vols in that pool. This would affect migration as migration is triggered through the hi and low migration point. If I put an equal amount of new volumes into a disk pool and set the old volumes to read only, a q storage will show the availability as double (old vols + new vols). Since the old vols were set to read only, backup data can only fill up to 50% because it can only go to the new volumes which account for 50% of total storage in that pool. Migration is set to go off at 80% utilization which would never take place since it can only go up to 50% max (new vols=readw, old vols=reado).

My question would be is TSM smart enough to realize that the old vols are read only but account for 50% of total storage in that pool and the stgpool can only be filled up to 50% with the new vols?

Also another question is if you have a disk pool filled with data and you vary it offline, does that damage the data on that pool? Will you be able to vary it back online without incident?

Thanks,

Ben

Ben,
Question 1: Changes in access status to a volume has no bearing on the size of the storage pool, it only affects accessability to the volume. Set to read-only will allow all read functions to continue, just no further writing will be permitted.
Question 2: Varying the volumes to read only, or changing their access to any status will not affect the data on the volume.

Suggestion: IMHO, If you have added additional volumes to the disk pool you have two options; 1) Migrate the data to another storage pool lower in the storage hierarchy, then delete them. If they are cached sick pools you will neeed to specify the discard data option. 2) perform a "move data" command on the volumes you would like to retire, then delete them as outlined above.

Hope this helps...

~Rick