ASM will see all disks that match asm_disk_string init.ora parameter of ASM. On all nodes. So you can use this parameter to control which disks every node sees.
Now, you can mount or unmoung diskgroup using ALTER DISKGROUP <dg> MOUNT/DISMOUNT;
ASM_DISKGROUPS init.ora parameter controls which disk groups are mounted at startup. It also used to mount umount disks using ALTER DISKGROUP ALL MOUNT/DISMOUNT.
Note that ALTER DISKGROUP <dg> MOUNT/DISMOUNT with specific diskgroup name modifies this parameter in spfile if you have one.
Now regarding CSS. In my understanding it has nothing to do with association of diskgroup to ASM instance. As I mentioned this is controlled by you or ASM instance at startup base on init.ora parameter ASM_DISKGROUPS. What CSS is tracking is association between database instance and ASM instance that it's connected to.
If you have the link to the presentation - please share. I would like to see it - maybe my understanding is incorrect.
If I have 3 Node RAC and is it possible that I can have 2 node using DG1 and DG2 disk group while third node can have three Disk group DG1, DG2 and DG3. Actually I want to use node 3 for one different application comparision to Node1 and Node2 and so want to use seprate Disk group.
I was in IOUG and have seen one presentation where they have shown it. They also mention that group services maintainted the DG+asm mapping. I know CSS is maintaining this information but is it possible to check the group services information outside of Database.
Kevin Closson <kevinc@xxxxxxxxxxxxx> wrote:
no problem...just the tip of the ASM misunderstanding iceburg out there...and that is no reflection on you...it is rampant
________________________________ From: Sanjay Mishra [mailto:smishra_97@xxxxxxxxx] Sent: Tuesday, June 13, 2006 5:49 PM To: kevinc@xxxxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx Subject: RE: ASM Record Deletions
Thanks Kevin for nice catch
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