4 Replies Latest reply on Nov 15, 2019 6:00 AM by TheBobkin

    With 2-node vSAN clusters, why not always choose "Full Data Migration" for maintenance mode?

    drheim Enthusiast

      Hey guys,


      We have a 6.5u2 cluster(disk format 5) that needs to be upgraded to 6.7u2(vsan on disk format 7).  There are only 2 nodes in the cluster and I need to upgrade them to 6.7u2, which also involves some firmware upgrades after, etc.  When putting a 2-node vsan cluster into maintenance mode, is there any reason you should not choose "full data migration" every time?  If it was more than 2 nodes, I know it might cause it to start re-striping the array, etc. which might not be needed if the server is only going offline for a few minutes, but with only 2 nodes I was thinking it should just be a copy(raid 1) between the 2 nodes, so why not always mark if as "full data migration"? That way you can shut it down as long as needed without having to worry about the Repair Delay Timer, etc?


      The reason I ask is because a few months ago I put one host into maintenance mode and took it offline for an hour or so for hardware maintenance and when I brought it back up the entire environment crashed as soon as it came up.  It hit us hard.  I never even brought the offline server out of maintenance mode and the primary node dropped all storage for some reason when it started to re-sync or something.  I got it back online, but spent hours with VMWare Support on this and they never knew why.  My best guess was that I chose "Ensure Accessibility" and went over the default 60 minute repair delay timer, but VMWare support never had any ideas after 12 hours of looking through everything.