Install vCenter and ESXi 5 on new hardware; migrate existing 4.1 hosts and migrate their guests

[greenpride32]

I have an existing ESX 4.1 10 node cluster that needs to be migrated to a new ESXi 5 installation.  I have 8 new servers that will be the ESXi 5 hosts.  My plan is to do a fresh install of vCenter 5 (do not need to import objects from the existing ESX 4 environment), install ESXi 5 on the 8 new servers and create a cluster, disconnect a ESX 4.1 host from vCenter 4 and add it to the cluster in vCenter 5, vMotion all the guests from the migrated ESX 4.1 host to the new ESXi 5 hosts, and shutdown and remove the migrated ESX 4.1 host.  If this goes smoothly I will repeat the process for the other 9 ESX 4.1 hosts.

Any caveats to this approach?  I am hoping the guest VM's can be migrated to the ESXi5 hosts without downtime.

Since I am mixing older hardware with new in the same cluster, I assume EVC needs to be enabled for the cluster.  Once all the older hardware ESX servers have been cycled out, can I disable EVC mode for the cluster?

I want to skip the step of upgrading the existing ESX 4.1 hosts to 5 as an intermiediary step since those servers will be decommissioned.  The new hardware for the ESXi 5 environment also gives me the luxury of any easy fallback to 4.1 if any issues arise.

[vMario156]

Yes thats possible. You didn´t mention your storage system. Version 5.0 introduced the new VMFS version 5, so keep in mind that you can´t svMotion a VM from a ESX 4.1 host to a VMFS-5 datastore (the 4.1 host will not even detect this datastore).

If you are using different hardware and can´t affort a quick reboot then EVC is an option. There have been some changes about EVC between version 4 and 5. With version 4 you just could enable /disable the EVC option without any running VM if I remember correct. With version 5, you can disable EVC on a cluster with running VMs, but for the single VM the changes should first become active after a reboot.

Regards,

Mario

[greenpride32]

All guests are on shared storage.  Can I simply present the existing LUNs the ESX 4.1 host is using, to the new ESXi 5 host, and then just migrate the guests to a new host (from the 4.1 host to the 5 host)?   If so, can I also convert the existing datastores from VMFS 3.46 to VMFS5?

[schepp]

greenpride32 wrote:

All guests are on shared storage.  Can I simply present the existing LUNs the ESX 4.1 host is using, to the new ESXi 5 host, and then just migrate the guests to a new host (from the 4.1 host to the 5 host)?  If so, can I also convert the existing datastores from VMFS 3.46 to VMFS5?

Yes you can vMotion the VMs on the shared VMFS 3.46 storage and also yes, you can afterwards upgrade the VMFS to Version 5. Even without VM-Downtime. But keep in mind that if you do that, you won't be able to fall back to ESXi 4.1 as you mentioned in your first post. Because 4.1 won't be able to see the VMFS5.

For Upgrading info take a look at this KB  article:

http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&e...

Regards

[vMario156]

It´s also worth mentioning that an online vmfs3 to vmfs5 upgrade isn´t the same as you format a datastore with vmfs5.

Regards,

Mario

[greenpride32]

Thanks for the link to the VMFS 5 conversion differences.  I suppose I will need to consider whether it is worthwhile to svmotion all the guests to newly formatted VMFS5 datastores as that would also be an option in m scenario.  I'd have to then wipe and reformat the legacy datastores to VMFS5 as they get cleared out.

[PalmerEldritch]

I'm planning to do almost the exact same thing.  Did this go smoothly?  Any gotchas I should be aware of before I begin?

Thanks!