host and storage groups on VNX

Question

Hello, Sorry for the newbieness of this question but I am somewhat new to this level of storage. I have taken over a VNX5300. It was managed by someone else in the past an is not optimally configured for our VMware environment as the person that managed it didn't seem to know much about VMware. Basically it is fairly simple, there are two VMware groups of hosts, called clusters, however they are not actual custers, they just called them that.  They have not been joined to DRS clusters. There are two hosts in one 'cluster' and three hosts in the other 'cluster' the hosts in one cluster are joined to one unisphere storage group and the hosts in the other are joined to a second storage group. I am redesigning and adding more hosts to the vSphere environment.  I am going to be retiring the oldest hosts and adding new hosts and joining all of them to a DRS cluster and then using resource pools to manage what happens under that... as it should be. I am trying to do this with no downtime. I want all hosts to be able to see all of the storage as it is all ESXi and I need this to make the DRS cluster work properly. It appears that it is not advised to have two storage groups assigned to one LUN. What is the best way to do this? Can I add hosts to more than one storage group?   so I could add all the hosts from one of the current storage groups to the other group, so one of the current groups contains all hosts, and then they could all see the same storage and I could remove the second storage group as it is no longer needed?  Can I do that without any interruption to service? I can probably arrange an outage time to do this if it is necessary, but it means waiting until the weekend and delaying the redesign. Appreciate any advice on if this will work, or any better way of doing it. Thanks Bill

dynamox · Answer

Bill,

a host can only belong to one storage group, a LUN can belong to multiple storage groups. So your goal is to combine both "clusters" into one ? LUNs currently presented to "cluster 1" storage group could be presented to "cluster 2" storage group. Discover datastores on "cluster 2", shutdown VM on cluster 1, browse datastore on "cluster 2", register VM and turn it on. One by one "move" VM over like that and then get rid of "cluster 1" storage group.

bill.dossett · Answer

ok, that answers question about host membership in storage groups... but I was hoping to not power down VMs.

My first goal is for all ESXi hosts to see all storage.

now thinking further about it... and with knowledge that as a swing time migration, I can add multiple storage groups to a LUN. I will bring the new cluster online and create an ESXi storage group. Add that storage group to all the LUNs and scan for storage. At that point my cluster can see the same storage as the older ESXi hosts. As this is all in the same virtual data centre, I can vMotion the VMs to the new cluster... without powering down. Once that is complete, I can do what I need to the older hosts, remove them from the old storage groups and add them ot the new ESXi storage group, and joing them to the cluster. Can anyone see a fault with that? And thanks for taking the time to look at this!

Jason_Zhou · Answer

Hi William, I am moving this thread to the VNX Support Forum space from the ECN Help Forum space as the latter is for asking questions regarding the EMC Community Network (ECN) platform itself rather than any EMC specific products/solutions. Thanks.

dynamox · Answer

if ESXi nodes are part of the same datacenter, yes you can use vMotion/Storage vMotion to juggle things around.

VNX

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