Hi All,
As part of the upgrade plan: Target Ontap = 9.5
ONTAP 9.1[Current] to 9.3 to 9.5 [step ugprade all in one go per cluster ]
We have multiplle cDOTs, but unlike traditional model where source & destination are clearly defined as separte controllers for source & DR, all cDOTs here are cross replicate each other, in short they are both source, and DR for other filers (Prod/DR both).
Concern : As these cDOTs run various PROD/DR envionmnet, we will do upgrade of each cluster one at a time. Which means, one cDOT will be at 9.5 and rest at 9.1.
Info: 90% are DP
Checking SnapMirror comatability matrix for type-DP:
https://docs.netapp.com/ontap-9/index.jsp?topic=%2Fcom.netapp.doc.pow-dap%2FGUID-0810D764-4CEA-4683-8280-032433B1886B.html
Results: 9.1 as source cannot have a destination of 9.5, period. And, b'cos of cross-replication, source will be at 9.5 and detinations will be at 9.1. Looks big NO NO.
Next thing I thought of is : Can version-flexible snapmirror rescue us ?
Good news I read: You can easily convert an existing DP-type relationship to XDP to take advantage of version-flexible SnapMirror.
https://docs.netapp.com/ontap-9/index.jsp?topic=%2Fcom.netapp.doc.pow-dap%2FGUID-0810D764-4CEA-4683-8280-032433B1886B.html
It further reads : Although resync does not require a baseline transfer, it can be time-consuming. That makes me smile b'cos of no re-basing.
Can experts advise if this approach will work, and any other precautions to be considered for what would be an staggered upgrade?
Thanks,
-Ash