As per my understanding if your requirement is to reduce the volume size or shrink the volume size then that is not possible. Please find the same captured from SMU guide,
"You can change the name and cache settings for a volume. You can also expand a volume. If a virtual volume is not a
secondary volume involved in replication, you can expand the size of the volume but not make it smaller. Because volume
expansion does not require I/O to be stopped, the volume can continue to be used during expansion."
https://support.hpe.com/hpsc/doc/public/display?docId=a00017707en_us (Page no 100)
Solution to this, you can take data backup, delete the existing volume and re-create the volume again. Then restore data from backup.
You need to understand the concept of Thin Volume and Thick Volume. You have created 4900GB of Thin Volume which means even if your system doesn't have that much space but hypothitically your volume in future can go up to 4900GB of space. For example, lets say you have only 2000GB of space at VDG but you have created volume size of 5000GB. Only condition this needs to be Thin volume.
In your case initially you have created 4900GB of Thin volume. Later you have deleted VDG named dg02 whose size 900GB so from Pool level it got reduced to 4500GB but your Thin Volume size will remain same at 4900GB. At this condition you can only expand the volume by adding more VDG to the Pool and then modify the volume size.
On the other size if you would have created Thick volume then you need that much space instantly because system will allocate that space for that volume.
Thin provisioning is a virtual storage feature that allows a system administrator to overcommit physical storage resources. This allows the host system to operate as though it has more storage available than is actually allocated to it.
When physical resources fill up, the administrator can add physical storage by adding additional disk groups, on demand.
If you try to disable overcommitment and the total space allocated to thin-provisioned volumes exceeds the physical capacity of their pool, an error will state that there is insufficient free disk space to complete the operation and overcommitment will remain enabled.
Hope this helps!
Regards
Subhajit
I am an HPE employee
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