We are in the process of migrating from an old EMC storage Array to a new EMC storage Array. We use ASM. The Oracle DBAs will be migrating from old disk volumes to new disk volumes using ASM "add/delete" in some cases and creating Clones in other cases. (I'm a Storage Administrator.) They now tell me that they need an outage on the server for ALL of the ASM instance to "release" the old disks; i.e. - they need to stop the ASM process. We can have multiple (1 -5) ASM SIDs on the same server or cluster (with CRS), and they will be migrating the SIDs one at a time. I asked them if they could "release" an old ASM device "on-the-fly" so that I could reclaim it from the OS (HP-UX 11.23), and they told me that "it doesn't always work...".
Is there a reliable way to "release" an old unused ASM disk "on-the-fly"?
This does not require a outage all you need to do is add in all the new disk to the disk group and then remove the old disk from the disk group. I would recommend you do this during a time when there is low IO activity.
I had the same issue several months back we need to move to EMC from IBM so we added all the disk from EMC making sure to match the total size of the diskgroup as well as taking into account mirror if you are using normal redundancy. Then we removed the old IBM disk. This was all done online and during the evening hours the work took about 5 hours to complete.