Melissa3055
Contributor
Contributor

Vsphere Essentials and Cluster

I have Vsphere Essentials 6.5.  Not Plus, so no VMotion or any of the other bells and whistles.  I have 2 hosts and a SAN on Vsphere Essentials 5.5 which I am going to decommission when I get new VMs created on the new hardware and 6.5.

In my existing 5.5 environment (2 hosts, SAN), a cluster was not created, but all the storage was shared between both hosts.  Due to space constraints, I have had to move specific VMs disks to a different datastore so it was very beneficial to see all the storage available.

In my new 6.5 environment (2 new hosts, new SAN), the storage was configured differently so that Host1 has 2 datastores visible and Host2 has 2 different datastores visible.  However the storage is not mapped to both hosts as it is in my 5.5 environment.  If I go to map the storage to the additional host, I get a warning indicating mapping a volume to more than one server can cause unpredictable results.  If you want to map to more than one server, you should create a cluster and map the storage to the cluster. 

So my question is, can I create a cluster strictly for the sake of sharing this storage and avoiding any corruption issues?  It looks like it will allow me to create a cluster and I can leave DRS, HA, EVC and vSAN off or disabled since I don't believe Essentials supports any of these.  I could map my volumes to the cluster and all storage would be visible to both hosts, so I could move (manually) VMs from volume to volume, host to host, as needed.  Most of the documentation references VMotion and other features which we don't have licenses for, so I am trying to determine the best setup for our small environment with the resources we have.

Any help is appreciated.  I can provide more information if I know what you may need to provide an answer.

Melissa

3 Replies
a_p_
Leadership
Leadership

I get a warning indicating mapping a volume to more than one server can cause unpredictable results.  If you want to map to more than one server, you should create a cluster and map the storage to the cluster.

This is most likely just a default warning as in most storage systems. However, ESXi with its VMFS file system supports simultaneous access from different ESXi hosts, so you can present storage the LUNs to multiple hosts.

André

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Melissa3055
Contributor
Contributor

So should I set it up as a cluster or just map it to both servers and ignore the warning?  Pro / Con of either?

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a_p_
Leadership
Leadership

I'd present all LUNs to both hosts. This will allow you to register the VMs to the remaining host, in case one of them fails, and you will be able to migrate them (powered off) from one host to the other if needed. With vCenter Server in place, this will ensure that each VM is registered to only one of the hosts. In case you don't want to use vCenter (for whatever reason) then it's your responsibility to ensure that each VM on the shared storage is only registered on one of the hosts.

André