How to tell if my SAN is Active/Active or Active/Passive

[sdotsen]

We have an AX-150 we purchased from Dell. We were getting awful performance from it and then switched to our CX3. Performance is so much better but I'm starting to think if I had the RDM set up correctly. With the AX-150, I had the RDM set to MRU. If it were Active/Active I have to set it to Fix, no? I googled and couldnt find what I need.

[kooltechies]

Hi,

Have a look at this.

http://www.vmware.com/resources/compatibility/pdf/vi_san_guide.pdf

Thanks,

Samir

P.S : If you think that the answer is helpful please consider rewarding points.

[Lightbulb]

IIRC In the CX-30 you will need to login via Navisphere and right click on the the Clariion (It will be APMxxxxxx) and chose connectivity status. This will show you a list of your host definitions. Click on the host and pick button called Info (I think). There should be a field with failover type. This will be a numeric representation 1,2,3 etc you will need to google or login to powerlink to determine which number maps to which failover method.

When I get home tonight I will take a closer look I am doing this from memory and do not have what I need in front of me. I think by default the Clariion will be A/A but don't hold me to that.

[richardmcmahon]

Clariion processing is handled by 1 processor at a time. Multiple paths pass to the single processor. When you bind a lun you select which SP it should default on to. The statement mentioned earlier is correct for individual Luns. You can have 2 seperate LUNs, 1 running on each SP. Multipathing on ESX3.5 exists but is not an active active load sharing setup like you would have with powerpath on a linux/windows box. Only 1 storage path is active at any one time.

Hope this makes sense

Richard

[mcowger]

ALL Clariion arrays are Active/Passive (aka ALUA) arrays, regrdless of what EMC's marketing says.

--Matt

[Lightbulb]

I learn more from this list than it is likely to learn from me. Good info.

[BUGCHK]

ALUA and Active/Passive are two different things.

ALUA (Asymmetric Logical Unit Access) means I/Os can be done through all paths to the internal storage resource (LUN, logical/virtual disk, partition, volume, ...), but some paths offer more performance, because they are presented by the controller/storage processor which owns/manages that resource. The non-performance paths will internally redirect the I/O to the owning controller.

A/P means that you have I/O paths through which you can't do I/O

(the passive/standby ones). A SCSI LUN is still presented so that the

multipath filter in the host operating system is aware of this paths,

can switch to them and tell the storage array to do a controller failover/transfer of management ownership of that

internal resource.

(oh, I love the mixing of terminology from different vendors...)

[mcowger]

Agreed - either way, neither of them is Active/Active, even though EMC calls them that on the newer CX4s.

--Matt