Multipathing confussion

[AtlasAdmin]

I'm in the process of configuring a 3 node cluster using ESX vSphere on HP Proliant DL360 G6 hardware in the office. We have decided to dedicate 2 of the 8 network interfaces to connect to our MSA1510i iSCSI using software iSCSI initiators.

As one the primary SP on our MSA enclosure has been configured with the IP address 192.168.51.18/24, originally I was under the impression that both the ESX iSCSI ports should be configured within the same subnet, and thus configured the interfaces with IP addresses within the 192.168.51.*/24 subnet.

Our storage admin is now telling me to configure one of the interfaces with the IP in the subnet 192.168.52.*/24 to be able to connect to the second SP that we have configured in the MSA enclosure.

Can anyone confirm whether this is a valid configuration for configuring multipathing with software iSCSI initiators?

Regards,

Paul

[VMmatty]

I'm not sure why you'd configure the interfaces on different subnets than the SP on the SAN, but I haven't worked with that SAN specifically so maybe it has different requirements.

The best post I've seen on configuring multipathing in vSphere is the following. It gives a rundown of how to configure it using the new Round Robin MPIO option available in vSphere. I strongly recommend you read it, even though it is pretty long as it is a fantastic post.

http://virtualgeek.typepad.com/virtual_geek/2009/09/a-multivendor-post-on-using-iscsi-with-vmware-vs...

[AtlasAdmin]

Thanks for the reply VMmatty. I think I've come across that virtual-geek link before but it's always good to have a reread just incase.

I might not have explained myself clearly enough. What I'm trying to figure out is whether it is possible to configure ESX multipathing using the vSphere iSCSI software initiator whie all VMKernel ports belong to differing IP subnets.

Our MSA1510i iSCSI enclosure has two controllers configured in an active/passive configuration. One SP (Data port) has been configured with the IP address (192.168.51.18/24) while the other SP (Data port) has been configured with the IP address (192.168.52.18/24). The second dataport is configured in a standby state.

As these two IP addresses belong to two different subnets, I imagine that I'd need to configure one of each of the vmkNIC in each subnet. As I've not found any documentation covering such a configuration, I'm not sure whether this is a valid configuration for iSCSI mutlipathing.

Regards,

Paul

[TobiasKracht]

iSCSI multipathing with esxcli! Exploring the next version of ESX

SAN Design guide

StarWind Software R&D

[ChrisJ615]

Here is what my configuration looks like. This config works for two iSCSI SAN Array configs. I hope this helps.

[ChrisJ615]

Oh, BTW: I have 4 ESX4 nodes in my cluster. All of the VMKernel's for MPIO are configured sequentially.