Years ago I was told two things, which I think are both incorrect, first that shelf ID numbers are not HA pair specific, meaning another HA pair in the same cluster cannot share the same shelf ID, secondly that you shouldnt use Shelf ID 0. Pretty sure its the opposite of these that is true. Interestingly this was a combination of a NetApp partner and NetApp support which told me this. Just wanted to get the community confirmation on this?
#Shelf ID Numbering
shadow rover
sinful wigeon
As far as im aware, they can be the same in a cluster, but i always find it easier to admin if the stacks/shelves are different. The exception here is Metrocluster where there is actually a spelled out best practice for shelve numbering.
I've heard the don't use shelf 0 thing because shelves ship with 00, so you don't want to acidently add another shelf with 00.
reef panther
Shelves with ID 0 is definitely possible but I also wouldn't recommend it. For example with AFF A250 you can't change the ID of the internal shelf included in the controller-chassis which always is using ID 0. So in that case you would be forced to change your shelves to other IDs.
Here's a good guide: https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Software/ONTAP_OS/What_are_the_best_practices__of_shelf_numbering__for_attaching_SAS_shelves_to_a_storage_system%3F
simple field
Personally I always used 10/20/30/40/etc for different stacks. Never single digits, mainly because of that shipping and new shelf installations potential conflict.
That said, I don't think we ever had more then 3-5 shelves per HA pair so I was able to get away with that.
visual grove
Add to this - ONTAP even has a last resort method of dealing with duplicated shelf IDs on an HA pair, so even if you mess up and plug in two shelves with the same ID to the same HA pair it will work, but internally you’ll get a weird disk ID like 0a.2948261849011abcd.02
shadow rover
Personally I always used 10/20/30/40/etc for different stacks. Never single dig...
Yep we do the same. However we've got to the stage where we've used up all the combinations almost. Hence the question about per ha pairs. I think avoiding 0 generally makes sense.
shadow rover
Add to this - ONTAP even has a last resort method of dealing with duplicated she...
Yeh I think the procedure involves powering down the nodes
sinful wigeon
yeah, you have to power cycle the shelf to set the new ID. so power down the nodes is needed.
blissful ermine
Regarding the shelf ids…
Think of if this way…how much easier is it to find disk 2.10.22 if there’s only one shelf 10?
Having unique shelf ids in the cluster makes troubleshooting so much easier. I knows it doesn’t happen often, but occasionally a disk fails and the LED cannot be turned on. If I have 2 or 3 shelf 10s, which one is it? Now I need to figure out which ha pair which rack. Not so easy.
I had a Netapp PS dude setup a storage grid with 4 nodes. He thought it was just fine to leave all four shelves set to default 99!!