MSA 2052 Dual Controller

[Staylor76]

Does the MSA 2052 dual controllers - run by default in an ACTIVE-ACTIVE or ACTIVE-PASSIVE state ?

We are currently installing the MSA - the DL360 Gen10 has a single SN1100Q Dual port 16gb FC card, port 1 connected to controller A - port 2 connected to B,  we can only see 1 initiator in the MSA GUI HOSTS page ?  is this correct and does this mean the MSA is running ACTIVE-ACTIVE ?

[Sahana_S · Accepted solution]

Hello @Staylor76 ,

In both write-back and write-through caching strategies, active-active failover of the controllers is enabled.

When ULP is in use, the controllers' operating/redundancy mode is shown as Active-Active. ULP appears to the host as an
active-active storage system where the host can choose any available path to access an LUN regardless of disk group
ownership.

Hence the default state is Active-Active.

I hope this is useful!

Thanks and Regards,

Sahana S.

[JonPaul]

@Staylor76 
I don't think that your question was fully answered.  When connecting a dual port HBA to the MSA you should see 2 initiators.  I believe that there is some blockage that is not enabling your second path from the HBA to the MSA.
Things to check:
CLI>  show ports      {do you have link on a port on A and a port on B}
CLI>  show initiators    {You should be able to see the WWPN (World Wide Port Number) for each of your HBA ports}
if you are connected to an FC switch, you should be able to see both HBA ports and MSA Host Ports connected (not your case)
ACTIVE-ACTIVE vs ACTIVE-PASSIVE is an easy and complex answer.  The system is ACTIVE-ACTIVE but each Pool is owned by a controller and that controller's ports are OPTIMIZED for I/O.  The other controller's ports are UN-OPTIMIZED according to ALUA (Asynchronous Logical Unit Access) standards. If you only have 1 Pool AND your multipathing solution is setup correctly, you will only see activity on one controller until that controller is unavailable this will look like an ACTIVE-PASSIVE configuration.  If you have 2 Pools then I/O for the volumes on the A pool will go through the A controller ports and the volumes from the B pool will go through the B controller ports.  

[Staylor76]

@JonPaul  - thank you.

using the show ports command showed us that the SFP on controler B had failed.

We replaced the SFP and now everything is working !! woooooohoooooo

thanks again.

[Sunitha_Mod]

Hello @Staylor76,

That's excellent! 

We are extremely glad to know the problem has been resolved and we appreciate you for keeping us posted.