ISCSI Active (I/O) path

[VinceStrem]

A couple of separate scenario with the same question.  The first set is my main storage is an EMC VNXe 3200 system.  I am port 2 and 3 in both SP A and B.  For port 2, SP A is set to 10.10.100.10 while SP B is 100.20.  For port 3, is is 100.30 and 100.40 respectively.  All 4 ports are connected to a 10GB switch. 

The ESX has two 10GB port vswitch that is set 10.10.100.110 and 100.100

When I check the path to the datastore, I am seeing 4 as Active (I/O) and 4 as Active.

In my other setup, I have twol 10Gig ports in my RS3413xs+.    First port is set to 10.10.200.50 while the 2nd port is set to 10.10.200.60.  The 2 ports are connected to a 10GB switch.  The server has a vSwitch with 2 NIC assigned.  both are 10GB with one having an address of 10.10.200.110 and the 2nd one with 10.10.200.100.  They are connected to the same switch as the Synology.   When I look at the path, I see 4 path to the Synology, 2 at 200.50 and another 2 at 200.60 however, only one path is Active (I/O) while the other 3 is Active

Is there anyway where I can get all the path Active (I/O)?   In the case of Synology, why am I only able to have 1 path that is Active (I/O)? 

Thanks

Vince

[VinceStrem]

I just figured out how to make all my path Active (I/O) for the Synology.  Just going to manage path and changing the path selection to Round Robin did the trick. 

But for the EMC, still only 4 are Active (I/O) while 4 are just Active.  Is there a limit?

Vince

[Shaun_ec]

I would assign each nic to a separate switch and then also have each Nic on separate subnet

[kastlr]

Hi Vince,

this "limitation" is by design.

A VNXe is an ALUA (Asymmetric Logical Unit Access) array, so even if the array has two service processors, IO's to a LUN has to occur via the primary service processor.

The other service processor could also handle IO's to that LUN, but it will reroute them internally to the primary SP.

If you want to use all paths to a LUN you would need to have an AA (active/active) array.

You could force VMware to use all paths to a LUN on the VNXe, but I wouldn't recommend to do so.

The internal IO rerouting will add an extra load on the array and it could also end in trespass storms which would highly impact performance of the total array.