Upgrade 6.0 to 6.5 with new hosts - new cluster or not

[nizuwizu]

Hi,

We currently have a small cluster of ESXi 6.0U2 hosts using shared storage. We are about to add an additional six hosts which we will install ESXi 6.5U1 and we will then upgrade our current production hosts to the same version (ESXi 6.5U1).

We have already upgraded vCenter to 6.5.

My initial thoughts were to

1.       Create a new cluster for the new 6.5 hosts

2.       Migrate using vMotion some VMs from the original 6.0 cluster

3.       Gradually upgrade the original ESXi 6.0 to 6.5 using VUM and then move them into the new cluster

4.       Continue migrating VMs to the new cluster and upgrading the ESXi 6.0 hosts

Or do I just add the new 6.5 hosts into the production cluster with the 6.0 hosts without the need to create a new cluster? I assume if I wanted to use this approach I should initially create some affinity rules specifying that VMs should run on either the 6.0 or 6.5 hosts so that I can control their migration (vMotion) in case of any unexpected results?

Having not created the production cluster initially I assume if we wanted to create a new cluster I just need to replicate the settings that are on the Configure tab of the current cluster?

I understand that I would need to continue using hardware level 11 and that if we created any VMFS-6 datastores on the 6.5 hosts that the VMs hosted on them would need to remain on ESXi 6.5

I would really appreciate some views on the best method and if there are any issues that I need to consider.

Thanks a lot.

[daphnissov]

If old and new hosts will eventually be in the same cluster at the end, you could just add the 6.5 hosts into the existing cluster. Some things to keep in mind when bringing online net new 6.5 hosts:

1. Make sure the (presumably new?) hardware will be CPU compatible with old hosts, either through EVC mode or what have you. You cannot include AMD and Intel hosts in the same cluster and cover under EVC.
2. vMotion must have connectivity across all members in the cluster, from 6.0 to 6.5, else you won't be able to migrate those VMs.
3. Ensure your shared storage has its microcode checked to be compatible with 6.5.
4. Check with the official documentation from your storage vendor to apply any specific tunings and tweaks keeping in mind you'll have, for a time, a cluster of mixed versions.

[nizuwizu]

Thanks for comments.

1. Yes i have checked the compatibilty and i will need to keep EVC mode at Sandy Bridge for the moment to be compatible with oldest host
2. vMotion should have connectivity across all hosts as they will be using the same shared storage and VMKernel network
3. & 4. I have to apply a update to our storage for its compatibility with 6.5 - i assume that is what you mean

From your comment i assume either way would be ok? i.e using a new cluster or not

I think my initial thoughts on creating a new cluster and seperating were also because at this stage we were also thinking about creating new datastores at VMFS-6 for the new hosts and this felt like another reason to seperate the ESXi 6.5 and ESXi 6.0 hosts (although i am less sure we will do this now and perhaps stay with VMFS-5). Would a new cluster in this scenario make more sense?

If using a new cluster is it just a case of replicating the settings that are on the Configure tab of the current cluster in the vsphere web client?

If continuing to use the current cluster would it make sense to apply affinity rules to control the migration (vMotion) between 6.0 and 6.5 hosts or is there a better way?

This would be while the upgrade and migration is taking place which will likely take a number of weeks if not months.

[nizuwizu]

Hi again,

The feedback i have already had was very useful but has anyone any further thoughts on this please?

Thanks

[a_p_]

From what you wrote, the only reason to have separate clusters is the VMFS version that will be used. However, in this case I'd likely add the new hosts to the existing cluster, and consider a VMFS upgrade at a later time, when all hosts are on v6.5. This way you will have all computing resources available during the VMFS "upgrade" period.

André