MSA260 SAS Port redundant

[Be5]

Hi

With MSA 2060 SAS

One Server is connected via both controllers, Port A1 and B4. First question do we need to connect to B1 instead of B4?

Here redundant is ok.

Here redundant is NOT ok (Port). Is that normal?

Second Port vmhba1P2 ist the same.

Thanks

[Be5]

Another question. All host are vmware esxi hosts.

At the moment the LUNs are configured like in the picture. What is the correct configuration all host same id or not? and with second datastore?

[Be5]

Question about redundancy i think is answered, the single ports are never redundant only the two hbas together.

And do we need to connect to B1 instead of B4? This was an installation mistake, changing would be time-consuming because the vmware datastore would have to be integrated again...

LUNs: What is the correct configuration all host same id or not? and with second datastore?

[JonPaul · Accepted solution]

Hi @Be5 

As to your first question:  Do the HBAs from a single host need to be in A1 and B1 or can they be in A1 and B4?
It is typical to put them into the A1 and B1 slots but is not required.  You can edit the mappings where the LUNs/Volumes will be presented out of only a subset of the ports and this is complicated by connecting to A1 and B4.  In the WebUI (Storage Management Utility, SMU) you can present/map to port 1 == A1 and B1. Mapping to only A1 and B1 is a slight security enhancement that other ports won't have that LUN presented.  I state slight enhancement as the explicit mapping already limits what can be seen and you would only have a problem if you have a duplicated Host HBA Unique identifier.
You can change this at any time as the LUN is presented to BOTH HBA ports.  Choose a time of low activity and swap the cables while the system is running.  Just don't pull both the A and B port for a host at the same time.  The MULTIPATH software for VMware will detect the path being removed and use the non-optimized path and then when the path is back it will return IO to the optimized path.

I believe that you correctly deduced that the 2 HBA ports have to be in the same Host for the redundancy parameter to align the 2 unique identifiers with a single host and determine that the host has a path on the A controller and a path on the B controller

Lastly: Should the same volume be mapped to the same LUN ID on all the hosts?
Mapping all the hosts to the same LUN ID for a single volume is typical but not required.  It can get confusing when troubleshooting that on Host-A the LUN ID is 1  but on Host-B the LUN ID is 2.  The OS will use the SCSI serial number for the volume to identify multiple paths so the LUN ID is more for the human readable information.

[Be5]

Thanks!