StoreVirtual: Replication Between Physical and VMware Volumes

[rianui]

Hello Gurus,

I have a client who recently bought four StoreVirtual 4530 storage nodes. Two will sit on the Primary site while two will go to the DR site.

I have set up the P4000s before but the requirements here are different this time. He has four physical servers that will be presented with storage on the primary cluster nodes. However, on the DR site he will have four VMs and wants those presented with four volumes as well then all four volumes from both sites to replicate. Is this achievable? Physical to virtual servers?

Regards,

Rianui

P.S. This thread has been moevd from Storage > General to HP StoreVirtual Storage / LeftHand. - Hp Forum Moderator

[a_o]

 The short answer is it depends on what their HA RTO and RPO are.

LH does not offer  LUN to LUN synchronous  or Async (CDP type) replication per-se.

What it offers - Network Raid - can be  considered as an in-LUN real time replication.

That is,  you can have 2 or more copies of your LUN available on your SAN. But it's still one LUN, accessed via a single IP.

Normally, each LUN can be accessed by a single host without causing any problems.
But by using a clustered file system like VMFS or CSV, more than 2 hosts can access the same LUN.
Also, in theory since in a SAN/IQ multi-site cluster, data access is prioritized based on  network proximity, the hosts on the Primary site will access the LUN by connecting to the SAN on their local subnet and the DR site hosts  will access the LUN by connecting to the SAN on their own subnet.

However,  my suspicion is that's not what your customer is trying to do.

One solution:

Since StoreVirtual offers remote snapshotting as a standard feature, you can replicate a LUN in a non continuous way (i.e.  in 1 minute intervals) to a remote cluster. This remote snaphot  could now be  stood  as a LUN when needed.

With this solution, your DR VMs will need to be stood up after the 'replicated' LUNs have been stood up.
This way, the newly stood up LUNs can be presented to your VMs...
Obviously, you'll have to reverse this setup for your physical hosts. You'll end up with 8 or more LUNs.

A simpler solution:

Simply use Storevault's Multi-site Clustering feature.
Put half of the StoreVaults in the Primary site, and the other half in the DR site.
Add a FOM to your Management group that is in a 3rd site that the Primary and DR sites can connect to independently of each other.
Create 4 LUNs in your multi-site cluster.
Create a Server Cluster in StoreVault that includes all of your hosts (Physical and Virtual)

Configure and point the hosts on both the Primary and DR sites to these LUNs via  the single vIP...

Lastly make sure that hosts from only one site can connect to the LUNs at one time. This means that your VMs should be stood down while the physical hosts are running. Depending on the apllication, using VMFS might negate the need for this.

[rianui]

Hi A_O,

First, thank you for the response that set me in the right direction.

I have created a multi-cluster with all four nodes in it, placing two on each site.

I then added a FOM to the Management group and created a couple of hosts and LUNs withing the cluster. What I didn't quite get from what you explained is the following:

Configure and point the hosts on both the Primary and DR sites to these LUNs via  the single vIP...

Lastly make sure that hosts from only one site can connect to the LUNs at one time. This means that your VMs should be stood down while the physical hosts are running. Depending on the apllication, using VMFS might negate the need for this.

- I used the ESX host IP address as the VIP. Is this correct?

- I dropped a file on one VM and when i scan it on the second host it needs reformatting....thus losing anything i'd copied therein

- What do you mean by VMs should be stood down? How do I go about that?

Regards,

Rianui

[a_o]

What do you mean by VMs should be stood down? How do I go about that?
I mean the VMs should be shut off or "powered down".

I used the ESX host IP address as the VIP. Is this correct?
The VIP is the StoreVirtual cluster's IP address.

OK. It seems that you didn't fully understand the options that I gave you.
It also seems you're leaning towards the Active-Passive solution.
Even if you're not, you'll need to share the storage between the hosts.

The key to this solution is to use VMFS as the storage sharing implement.

If your VMs access the LUNs directly, you'll run into the problem with the second host saying that it needs to  format the LUN. This is because two hosts are accessing the LUN at the same time. You need a clustered file system for that.
Windows does not have a native clustered file system, unless you're using HyperV CSVs.
Ergo, VMFS.

You need to present your storage to your VMs using VMFS.

Take a look at these links:

http://pubs.vmware.com/vsphere-4-esxi-installable-vcenter/index.jsp#introduction_to_storage/c_sharing_a_vmfs_volume_across_esx_systems.html

http://pubs.vmware.com/vsphere-4-esxi-installable-vcenter/index.jsp#introduction_to_storage/c_how_virtual_machines_access_storage.html

Also, realize that you'd have to virtualize all of your hosts.

[rianui]

Hello A_O,

Again, thank you for your time and response.

I haven't done much since yesterday. Power went out on the DR site and the two nodes on that side are having manager issues "Manager Starting/Stopping". After investigating this with L2 support, I was advised to reimage the nodes. I got stuck with the original license keys not working so I'm now waiting to hear from the Licensing team. I will update my progress once the hardware mess is sorted out.

Regards,

Rianui