ONTAP Hardware

Strech metrocluster - Adding independant shelf


Hi all,


i have a strech metrocluster composed like that :

 - 2 FAS 8020

 - 2 DS2246 (24x900)


As this is a "strech", there is no ATTO, only many fibers between them. Looking behind it i can see cabling is quite complicated, we are going from Controller to shelf from each side (i did it some years ago, never tried again Smiley Happy )


We only would like to add one shelf on each side, but do not replicate . It should be seen as storage only by the "local" controler

Do i have to change all the cabling to integrate the new shelf into a kind of daisy chain, or could i use free SAS port on the controler to have this 2 new shelves plugged simply (i have 2 free ports one integrated 0B and one on an additionnal card)


Many thanks for you help






For failover to work (during upgrade etc) you should still have them cabled to both controllers.

You didn't specify the ONTAP version/mode, so hard to tell you what scenario is supported for your configuration.  but unless you already exceed some limit in the stack(s) - i don't see a reason why not to add them to the existing stack(s).

Gidi Marcus (Linkedin) - Storage and Microsoft technologies consultant - Hydro IT LTD - UK


Thanks Gidi for your reply.


Sorry i forgot to tell you that !


version is NetApp Release 8.3.1: Mon Aug 31 12:42:08 UTC 2015 clustered mode


Will it be easy to plug the new shelf into the existing daisy chain ?



Edit : i read somehow, and found also some docs that i had when i first installed it (please see attached pictures)

In fact it seems that adding a shelf do not need to add links between the all the shelf and the controller but only between shelf, exactly lake a daisy chain.

This is a good new as it seems simple.

And then it seems i'l be able to create aggr that won't be replicated.

Do you know if we can do it while running or should we do a takeover then shut down then physical plug then start again.


Any help is apreciated 🙂



It can be fairly easy if you understand the cable pathing rules.  


This can all be done while the system is running. "Hot add disk shelf"


Read the following two documents to understand what you are getting into.





Based on the drawings you provided and the desire to not have the new storage shared across the metro-cluster. You will need to create a new loop. If I understand what you're trying to accomplish.


I would call Support to make sure your desired configuration is supported.


In fact i understand/realized something while ready : a shelf can be shared throught the metrocluster without being mirrored.

And what i'd like to achieve is in fact : no mirroring, having it shared throught the cluster is still great.


Correct me if i'm wrong : i can insert the shelf into the actual loop, then use its capacity totaly without mirroring but shared accross the metrocluster.

I'll go throught your link and see, many thanks !


First a nag: 8.3.x ONTAP has passed End of Version Support.  You need to move to 9.1 or later if you want any kind of software support.

Reference: https://mysupport.netapp.com//info/web/ECMP1147223.html#ontap_svst


I don't see any reason why you couldn't use the same stack. By not mirroring the plexes (i.e. MetroCluster), you'll just have MP-HA SAS connectivity, stretched across between your two nodes. 


But if you want the official answer, open a technical case.


Really, many thanks to all of you, your replies and the reading after helped me a lot to be more confortable with that


Hi there,


juste a little feed back for someone that would have the same question :

 - following the diagrams that was attached to the beginning of the thread i was able with no problem to plug the new shelf

 - i did it while in switchover to be sure

 - when i wanted to create a new non-mirrored aggr it was forbiden, i had to upgrade to version 9 all the metrocluster to be able to do that


Hope this will be usefull