topic Re: MetroCluster cDOT: upgrade controller using ARL in ONTAP Discussions

MetroCluster cDOT: upgrade controller using ARL

RAFAEL_GUEDES — Thu, 05 Jun 2025 04:36:11 GMT

Hi,

I'm reading TR-4375 (MetroCluster for Data ONTAP Version 8.3) and I got confused about MC planned operation: upgrade controller using ARL (page 28).

TR states in MC "Aggregate relocation can be used to nondisruptively upgrade controller models in place; for example, to upgrade FAS8040 to FAS8080." And "Disk mirroring continues during the ARL process but NVRAM needs to be disabled."

Until here, OK!

But now it states "Therefore the aggregates stay in sync; if a forced switchover is necessary during this time, at most the last 10 seconds of transactions may be missing."

And my question is: if I've disabled NVRAM, how could I miss any transaction??

Re: MetroCluster cDOT: upgrade controller using ARL

aborzenkov — Mon, 13 Apr 2015 06:52:04 GMT

You can't disable NVRAM; you can disable NVRAM mirroring between locations. Which means you cal lose data since latest CP.

Re: MetroCluster cDOT: upgrade controller using ARL

RAFAEL_GUEDES — Mon, 13 Apr 2015 18:53:15 GMT

You are right. I was thinking about disable NVRAM as a whole, not only the replication between DR Partners. Thanks for helping!