Wednesday, 1 November 2017

vSAN ESXi Host Upgrade Using Update Manager

Part -2 vSAN ESXi Host Upgrade Using Update Manager

This post is part of step by step vSAN ESXi host upgrade process.

How to Upgrade vSAN ESXi Hosts
vSAN ESXi host upgrade is very time-consuming process. You should run health precheck tasks before upgrading each ESXi host. You can exclude hardware compatibility check once you are sure that your all servers are compatible with new version of vSAN/ESXi.
However, while putting host in Maintenance mode you need to select the vSAN data migration option.

vSAN host Maintenance Mode option

  1. Evacuate all data to other hosts – before host goes in Maintenance Mode all data from this host will be migrated to other hosts disks in the cluster, provided you have sufficient free capacity available. It will take some time migrate data to other hosts.
  2. Ensure data accessibility from other hosts – do not evacuate any data. Put host in Maintenance Mode, ensure data remain accessible from other hosts. VM objects will be unprotected.
  3. No data evacuation – No data evacuation, VM objects will be unprotected.  

Which Maintenance Mode option should I select for vSAN Host?

Try to answer below question to yourself to decide maintenance mode option.
  • How much critical data is it, Do I need to proactively rebuild data to other hosts?
  • Do you have enough free space to rebuild objects if one host fails?
  • How much time it will take to rebuild objects?
  • How much time it takes to evacuate all objects/data?
  • how long ESXi host will be down?

My Preference – I prefer second option, “Ensure data accessibility from other hosts” this is more useful and time saving. ESXi hosts would be back in couple of hours after patching, so no data rebuild or migration is required. Once ESXi hosts comes online it will rsync all objects. For some reason if ESXi host don’t come online then vSAN cluster will automatically start rebuilding objects to other hosts.

Vmware Update Manager Integration with vSAN

Vmware has integrated update manager with vSAN. Update manager automatically create and assign Update manager baseline to vSAN cluster as on when applicable patches gets released.
You can use this system defined patch/upgrade baseline or you can create your own patch baseline.
Once you upgrade one host, exit it from Maintenance Mode and run the health check again. Exclude hardware compatibility checks.
Make sure that vSAN health check plugin is not reporting any issues. If you notice Disk rebalance is happening wait for disk rebalance task to get completed before you start upgrading another host.
If you notice any issues after upgrading first host, fix those issue before proceeding with next host upgrade.
Once you upgrade one of the Host in vSAN cluster, vSAN Health plugin may report warning/errors related to vSAN advanced option mismatch or performance data. You can ignore these warning until you complete all Hosts upgrade.
But make sure you are not ignoring any warning/errors related to vSAN objects, disk usages, VM storage Policy compliance.

Next - Part 3 - vSAN ESXi Host upgrade issues

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