I'm getting used to the new concept of SGs, PGs, IGs and MVs on the VMAX 20k. After creating the Masking View everything is automatically mapped and masked. But what if I made a mistake and needed to back out. For example say I entered a wrong HBA WWN into the IG or a wrong port into the PG or a wrong volumes into the SG and then created the masking view.
Can I back this out simply by deleting the masking view? Or will I have to do some other manual work to clean up mapping/masking entries?
I'll be presenting a bunch of storage to a lot of mission critical hosts and want to make sure I have a good backout plan in case I make a mistake.
There is usually no need to complete delete the MV. You can simply modify the affected PG, IG, or SG.
You can certainly completely delete the MV if you'd like. Just make sure to use the -unmap option so that the mapping undone.
So I can simply modify the IG? For example if I found I had the wrong Initiator in an IG then I would simply remove it and add the correct initiator. But I'm guessing I would then have to run some sort of manual unmasking? Same deal with wrong WWN in a PG. Once I remove the wrong wwn and add the new wwn wouldn't I have to do some kind of manual un-mapping?
For an IG, all you need to do is remove and replace the WWN. No other operation is necessary. The MV it is attached dictates the masking automatically based on the associated groups.
As far as modifying PG or SGs, it is very similar. Simply removing and replacing will take care of all masking. If the volume should require an unmap, make sure to include the -unmap flag when you remove the device or port and the unmapping will also happen in the background.
Interesting, we use Unisphere. I'm guessing this will all work with Unisphere, simply remove and replace the item and everything happens automatically? I guess we would still need to rescan the bus on the Host. For PG or SG click on the "unmap" when removing a volume from SG or port from PG. Does this sound correct? Seems too simple.
Thanks for the help.