Can a VLAN for SAN use the same subnet as the admin/VM network?

[dfindlay]

This is an existing 4-node cluster. There are three virtual switches:

Vswitch0: admin network, service console 0 (10.1.1.15)

vswitch1: vm network, service console 1 (10.1.1.22)

vswitch2: vmkernel, service console 2 (10.1.1.42), vmotion, iSCSI SAN

If I create a VLAN containing only vswitch2 and the SAN, Vmware no longer sees the SAN.

I've read that Vmware looks for the SAN via the service console and then uses vmkernel to access it. Could it be looking for the SAN on one of the other service consoles first? Can I change the order? Am I on the right path?

It's going to be difficult to change the IP addressing of the SAN as this is a production system and I'd have to take everything down, change the addresses, and re-mount everything.

[patrickds · Accepted solution]

i think it will use vswif0 by default if they're all on the same subnet.

To accomplish what you want, you'll either have put the vmkernel port group on your first vswitch, or choose another network range for your storage VLAN, and you've already stated that option 2 is not possible.

Why do you have 3 service consoles on the same network?

[dfindlay]

There were originally only two service consoles. That was to make HA happy. I added the third one to vswitch2 in an attempt to solve this SAN/VLAN problem.

[patrickds]

if you want a redundant HA failover detection network, you should typically use a different network range. (service console on vswitch1)

I don't know your network configuration (physically), so i don't know why you chose to do it like you did.

Normally, having redundant backing physical nics on your first vswitch, should be enough to satisfy HA network redundancy, and the second service console is not required.

[Texiwill]

Hello,

For what to combine check out http://www.networkworld.com/community/node/35063

For NAS/iSCSI setup check out http://www.networkworld.com/community/node/34581

The short is that your iSCSI server should be on its own network or subnet/VLAN. Only one vmkernel device can be used per subnet/VLAN. If you can not ping and vmkping the iSCSI device then your iSCSI vmkernel portgroup and SC are not participating in the proper networks.

The first thing to do is run ping and vmkping to determine which is failing and why.

Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

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