EMC VNXe ISCSI Server selection for new LUN behaviour

Question

I'm hoping someone is more familiar with the EMC VNXe 3100 to tell me if this is normal behaviour, I am changing the storage around a bit and creating a new Hyper-V cluster so I have been making a few changes.

I originally had one ISCSI server setup that was attached to storage processor B, this is still active.

The storage NICs on both SPs are aggregated.

I created two new ISCSI servers ISCSIServerA (Storage Processor A) and ISCSIServerB (Storage Processor B) with the intention of spreading the load between the SPs however, when I go to add a new LUN I only ever get a choice of attaching them to the two ISCSI servers that are on SPB and not ISCSIServerA of SPA.

So I'm wondering is this normal behaviour or am I missing something ?

Swapnil_Chikhal · Accepted Answer

Hi,

Thank you for posting your question in EMC forum. Please find article understanding available space in storage pool

If most of the space is already been allocated to one storage processor, even after creating new iSCSI server on other SP doesn't give option to create storage on other SP.

As you mentioned that all storage was created on SPB that means most of the total space available in global pool was allocated to SPB. In this case VNXe doesn't give option to create storage on SPA.

It certainly depends how much storage is created on SPB and what kind of provisioning was configured.

Could you provide details of storage pool?

- Total space on storage pool

- Allocated space on storage pool

- Subscription level on storage pool

These information will give us clear indication why you are not able to create storage on SPA.

Regards,

Swapnil

Leo Li · Answer

Hey,You just need to know that1. When you create a iSCSI server, you can specify a SP(SPA or SPB) for the iSCSI server.2. After the iSCSI server creation, when you create Generic iSCSI Storage, you can also specify Storage Server as following screenshot.Hope this helpful. Please feel free to ask me if you still have question.

SSFMCHC · Answer

Thanks for this. The issue was indeed that all the storage space is allocated to one pool and therefore it is attached to one SP.

I think this needs to be changed so I need advice on how to reconfigure this:

I will be using this SAN to supply a Hyper-V cluster with storage for the operating systems for the virtual machines. There will be no mass file storage and access done from here as this is allocated to another SAN.

The current performance pool consists of 10 disks in RAID 5 giving 1.896 TB of storage.

There is a hot spare and 1 unconfigured disk !

I would like to stay as close to my current storage capacity as I can.

I want at least two pools so I can spread the load between the SPs

What pool size and raid levels should I be thinking of for this ?

Will I notice any performance level reduction if I am not using as many spindles for the pool that I am currently ?

Any advice greatly appreciated.

Swapnil_Chikhal · Answer

Hi,

As you mentioned that most of the storage is configured, In order to reconfigure storage to load balance You need to delete few production LUNs and reconfigured it on SPA.

Take backup of data from few LUNs

After ensuring that data is backed up, Delete those LUNs from VNXe and recreate it on SPA

Once LUN is configured on VNXe, restore backed up data back to LUN.

Regards,

Swapnil

VNX

EMC VNXe ISCSI Server selection for new LUN behaviour

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