MSCS and LOAD BALLANCING on the MSA1000

[Max Sorokin]

Hi Everyone,

Is it possible to configure LOAD BALLANCING on the MSA1000 disk array in MSCS enviroment?

[Uwe Zessin · Accepted solution]

No. Controllers are strictly Active/Standby. All logical disks are owned by a single controller at a time.

[Max Sorokin]

And what about static Load Ballancing?

[Uwe Zessin]

The answer is still NO, because only one controller is active at a time.

[Max Sorokin]

And what about this:

"So the best that you can do is static load balancing with SecurePath in a cluster. Use something like Perfmon to get an idea of what your disk access/load is like, and then set preferred paths in SecurePath, and split them up that way. It may take a couple of tries to get it well balanced."

???

[Uwe Zessin]

Sorry, but quoting some arbitrary paragraph [where did you get it from ?] does not invalidate what I have written.

You simply cannot load balance logical disks on an Active/Standby controller combination. Once you try to move one logical disk over to the Standby controller, it becomes the Active one and *ALL* logical disks come online here.

[Max Sorokin]

I think this quote about HSG-based storage. :)

[Uwe Zessin]

Right. It is for HSG and EVA storage where controllers have two host ports that present active/active LUNs so that a multipath driver can dynamically load-balance between them. And both controllers are active/active meaning that they can serve different units / virtual disks to the hosts.

But please be aware that even with these controllers, dynamic load balancing is not supported in all cluster environments.

[Max Sorokin]

In attachment there is a document where i find a table, which defines the combinations of operating systems and storage arrays on which Dynamic Load Balancing for clusters (MSCS) is supported. is it true or not?

[Uwe Zessin]

Max,
you need to read the whole sentence. I don't see a simple statement that says this is true.

Let's take the first sentence, for example:
""Dynamic Load Balancing is supported with Secure Path V4.0C for Windows and Windows Workgroup Edition **with certain storage systems** in a Microsoft Windows Cluster Server (MSCS) environment, as detailed below."

You see, it says "with certain storage systems".


Go to the table and you see that no listed operating system does support Dynamic Load Balancing on the MSA1000. It is not possible for the reasons I have written above (single controller port, active/standby controller).

[Glenn N Wuenstel]

Gentlemen,
Let me take a stab at this.
"Load Balancing" is a term that can be used many ways -- Load Balancing (LB) the servers or LB the HBAs or LB the Disks. Uwe was correct when he stated that the MSA is an active/standby system. Therefore the MSA cannot LB at this time (active/active is a future plan). However, you could use SecurePath to manually LB across multiple HBAs in your servers. You could also create multiple Luns and then in your MSCS create multiple resources and assign a LUN and IP Address to each resource. You can then manually move the resources amongst your cluster servers and thus LB your servers.
Hope this helps,
Glenn