persistent reservation

[Stefano_Colombo]

I've not been able to find if the VA7400 support persistent reservation.

We have two MSCS clusters .
Each node has two FC HBA .
I've installed autopath 2.0 and checked the "load balancing support" flag.
Later I checked with the autopath GUI client but the load balancing for the LUNs is disabled and I can only set a preferred path .
Notes in the readme file say that the device must support the persistent reservation.
Can anyone tell me if I'll be able to use load balancing in such envinroment ?
thanks

[Eugeny Brychkov]

Load balancing is an exciting feature, but for VA disk arrays in perfomance reasons you'd better use preferred path. Remember: for LUNs created within redundancy group 1 (RG1) preferred path should go through VA controller 1 (C1), but for LUNs within RG2 through C2.
Please also check if you have latest Autopath installed (2.0, and also CommandView SDM at least 1.06). If not please contact HP for obtaining software
Eugeny

[Stefano_Colombo]

We have autopath 2.0 and command view 1.06.

The "preferred path" refers to the HBA on the server or the controller on the VA ?

If I have TWO HBA does it mean that only is working ( if load balancing cannot be enabled ) or can I distribute the loads manually between them ?

[Eugeny Brychkov]

Of course. You distribute LUNs within VA, creating some of them within RG1 and some within RG2. Then, as I said, perfomance path for LUNs within RG1 is going through VA controller 1 (C1). So you choose one HBA so the path from this HBA goes through VA controller C1 for all LUNs within RG1. Then you choose another HBA so the path from this HBA goes through VA controller C2 for all LUNs within RG2.
This way you'll have LUNs balanced across all two HBAs and VA controllers
Eugeny

[kris rombauts]

Hello Stefano,

to answer your question, no you cannot benefit of the load balance feature in a Windows cluster because the VA7100 and VA7400 do not support the persistent reservation feature, it's not available in the firmware of those arrays. So the dual fiber HBA's in each server will work with Autopath in a failover mode.
The VA7110 and VA7410 however do support this.


You can benefit of the load balance feature in any other config (meaning no MSCS cluster).


You obviously will achieve some kind of I/O load balanced when you design your LUNs in the SAN properly accross the hosts you are using like mentioned in the previous responses but this is a different/general topic.

HTH

regards, Kris