ONTAP Discussions

Reorganicing disks on a CDOT metrocluster 8.3.1


Hello, i have a fresh installed small 10TB (20TB unmirrored) Metrocluster to manage, unfortunatly there was not much planning upfront and the company who set it up divided 50:50 and we want have 70:30.  It is CDOT 8.3.1 it has 2 24x Disk shelfs. 

Can i savely offline and destroy the MVP volumes, are there ways to save the data first ?

How can i destroy one half to built it new up with fewer disks?



Hi Mario,


unfortunately there is no way to destroy the MDV volumes. They are an essential part of the MetroCluster and required for replication of MCC-specific metadata.

The only chance would be to move the MDV volumes to a different aggregate, but I guess you don't have enough spare disks available to temporarily create one.


In case your system sends Autosupport, could you please provide hostname or serialnumber of one of the nodes? I could look into the layout and see if I find a way.


regards, Niels




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SN# 211547000226 yes it send autosupports.

I have all commands in the documentation which were used to create this metrocluster, but not the values which were put in any wizzards which maybe pop up. Can i disolve the cluster and rebuild it - how ? 


Hi Mario,


you can always rip and rebuild. But that's a rather lengthy process.

You would need to initialize all disks, which destroys the cluster(s) and everything that has been pre-configured.

You'd then need to follow the "MetroCluster(TM) Installation and Configuration Guide" that can be found here:



To keep the configuration you already have I'd suggest the following on the node you want to take disks away from:


- re-configure the RAID type for the existing data aggregate from RAID DP to RAID4. This will free up a spare disk in each pool

--> aggr modify -aggregate <aggr-name> -raidtype raid4


- create a small mirrored aggregate. You need to be in advanced mode to be able to create such a small aggregate (it will be expanded at the end)

--> set advanced

--> aggr create -aggregate <new-aggr-name> -diskcount 4 -raidtype raid4 -mirror true -force-small-aggregate true


- aggregate creation will take some time as the former parity disk needs to get zeroed.

- the system might complain about not having any spare disks left (this is expected)


- once the aggregate is created, move the MDV volumes to that new aggregate (still need to be in advanced mode)

--> vol show -vserver <node-name>

- move the volumes that listed as "online"

--> vol move start -vserver <cluster-name> -volume MDV_CRS_<some-ID>_A -destination-aggregate <new-aggr-name>

--> vol move start -vserver <cluster-name> -volume MDV_CRS_<some-ID>_B -destination-aggregate <new-aggr-name>


- offline and destroy the old aggregate

--> aggr offline <aggr-name>

--> aggr delete >aggr-name>


- disable disk-autoassign to be able to re-assign disks as you want them to be

--> disk options modify autoassign off


- reassign the disks to the node and pool you want them to be. DOUBLE-CHECK POOL ASSIGNMENT and leave anough spares for the cluster to grow the small aggregate and a spare per pool.

--> disk show -fields owner-id,owner,pool

--> disk removeowner -disk <disk-name>

- go to other node and perform disk assignment

--> disk assign -disk <disk> -pool <pool>


Now clean up

- reset disk autoassignment

--> disk options modify autoassign on


- change RAID type of the small aggregate to RAID DP

--> aggr modify -aggregate <new-aggr-name> -raidtype raid-dp


- add additional disks to the data aggregates at both sides (leave a spare!) For RAID DP an aggregate must contain at least 5 disks.

--> aggr add <new-aggr-name> -diskcount <number of disks>


- rename the aggregate

--> aggr rename <new-aggr-name> -newname <old-aggr-name>


- zero disks on both clusters by running the following command on both sides

--> disk zero spares


You are done.



regards, Niels




If this post resolved your issue, please help others by selecting ACCEPT AS SOLUTION or adding a KUDO or both.