MSA1500 Controller

[Muhammad Farhan Nasir]

Does an MSA1500 do true active/active performance? Fibre channel switch port traffic shows traffic only on one path to the MSA. MSA1500 reports:
Supported Redundancy Mode: Active/Standby Asym-Active/Active
Current Redundancy Mode: Asym-Active/Active.

but only one controller showing activity and second controller show on only Active LED on LED number "7".

is ther any problem in MSA controller or FW issue.

[Johan Guldmyr]

asym - asymmetrical active/active - meaning one controller owns the LUN and if requests come in through the proxy-controller it forwards the request.

Maybe your hosts are so smart (have the ALUA sensing MPIO/multipating software) that they only speak to the owning controller?

[Torsten.]

On active/passive configurations one controller owns all the LUNs, the other controller is just standby.

On active/active 1 controller owns a LUN and does the work, but the controller can own another LUN and do the work for this LUN.

Since passing over the data from the standby to the owner, the data should only be handled by the LUN owner (this is what you see).


But now it is a bit more complicated, since the disks are single pathed, the controllers have to "somehow" share the internal busses anyway.

[Torsten.]

should be

On active/active 1 controller owns a LUN and does the work, but the other controller can own another LUN and do the work for this LUN.

[Muhammad Farhan Nasir]

Thanks.
my all LUN Preferred Path is : "Controller 1"

possible to change LUN Preferred Path...

[Torsten.]

The manual (worth to read!) says:

"Auto is the default setting for new configurations. In this case, the storage system automatically selects the I/O path from the redundant controller to the logical drive and dynamically load balances all paths."

But you can also set it manually to controller 1 or 2.

[Uwe Zessin]

We need some more background information like what firmware is on the controllers (there was one code stream that was 'almost A/A' - it looked A/A, but run A/P)

and then what operating system and version is running on the hosts, because that defines how the multipath environment must be configured. The MSA might do 'automatic' round-robin assignment of logical disk ownership, but it can do ownership transfers like the EVA if too much host I/O goes through the non-owning controller.

[Muhammad Farhan Nasir]

OS is HP-UX 11.23