Unity iSCSI ports on the same subnet

Question

Hi, Customer has a new Unity which has 8 x 10Gbe iscsi ports, 4 per SP. But they only has one subnet. is it absolutely required to have separate subnet for each SP port? In this case, what option to do we have to make is work? Can we only use one iSCSI HBA, and one SP port per SP? Thanks.

DELL-Sam L · Answer

Hello DavidQY,

You want to have iSCSI connections on a different network than regular network traffic. If you are going to be doing any replication then you will need to have a minimum of 2 iSCSI connections per controller.

Please let us know if you have any other questions.

davidqn · Answer

Thanks a lot. so if we have a dedicated subnet for iscsi, does that allow the host to leverage 2 iSCSi initiator to access Unity? Or in that case, we need two iSCSI subnets? Thanks again.

DELL-Sam L · Answer

Hello DavidQY,

It is best to have two iSCSI subnets. You can use just a single iSCSI subnet for all iSCSI traffic, however if you are doing replication then you will want 2 subnets so replication can be on it’s own subnet.

Please let us know if you have any other questions.

davidqn · Answer

Thanks Sam.No we don't have replication. iSCSI only. I understand ideally we want to configure a host with two NICs as below, for load balancing and failover:NIC1 (for example, 10.168.10.180) - SP A-0 and SP B-0 iSCSI connections VLAN 200NIC2 (for example, 10.168.11.180) - SP A-1 and SP B-1 iSCSI connections VLAN 201 However in this case, we only have one dedicated iSCSI subnet. So if we configure as below, do we still get load balancing and failover on the the HBA and SP ports? I understand we don't have redundancy on the switch or subnet.NIC1 (for example, 10.168.10.180) - SP A-0 and SP B-0 iSCSI connectionsNIC2 (for example, 10.168.10.181) - SP A-1 and SP B-1 iSCSI connections Thanks again!

DELL-Sam L · Answer

Hello DavidQY,

You will still get load balancing. I would suggest that you alter your ports like the follow:

NIC1 (for example, 10.168.10.180) - SP A-0 and SP B-1 iSCSI connections

NIC2 (for example, 10.168.10.181) - SP A-1 and SP B-0 iSCSI connections

Please let us know if you have any other questions.

DELL-Sam L · Answer

Hello DavidQY, You can set it either way.  I have found that when customers setup using the way I suggested that they don’t have any issues. Please let us know if you have any other questions.

davidqn · Answer

Thank you Sam. Can you elaborate a bit more why we want to use different SP port for the same initiator? I thought we wanted to use the same SP ports for better failover? Thanks.

Unity

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