iSCSI multipathing issue

[fafa24]

Dear all,

I have a issue with configuring iSCSI multpathing for a new server with ESX 4.0

First please let me explain my configuration

iSCSI MD3000i Dell Box.

IP: 192.168.130.101

IP: 192.168.131.101

IP: 192.168.130.102

IP: 192.168.131.102

subnet mask for both networks 255.255.255.0.

Server 1 with ESX 3.5 installed

Vswitch1: IP 192.168.130.10

Vswitch2: IP 192.168.131.10

subnet mask 255.255.255.0 for both

both vswitch are configured with two physical nics

Server 2 with ESX 4.0 installed

Vswtich1: IP 192.168.130.11

Vswitch2: IP 192.168.131.11

subnet mask 255.255.255.0 for both

both vswitch are configured with two physical nics

The MD3000i box sees 4 path for server 1. I can verify it at the ESX conosle as on the MD3000i box

However the MD3000i box sees only 2 path for the server 2. Only the network 192.168.130.11. This I could verify on the MD3000i Box

I was playing a bit with the security profil for server 2 and suddenly the server 2 had 4 paths too to the MD3000i box.

A few days later it was back to two paths again. The only thing I did; I was applying Update 2 rollup to server 2 with Update manager. The build of server 2 is now 4.0.0.261974

Server 2 is not yet in production.

I don't know why the paths were lost after applying rollup 2. Security profil looks fine and all network nics are up. I verified all network settings and everything seems to be set as it should be.

Can you help please?

Thank you

Edy

[a_p_]

Did you double check the configuration on the physical switch ports? (e.g. for Cisco: spanning tree port fast, switchport mode access)

Can you "vmkping" the storage from the host?

Do you use VLANs? If yes, where did you configure the VLAN ID, on the physical switch or on the virtual portgroup?

André

[fafa24]

I do not use VLAN.

How can I ping the iSCSI networks from the ESX console? I never figured that out. Could you please tell me?

I use two separate Dell Powerconnect switch just for the iSCSI network. Each switch is for a network.

Thanks

Edy

[a_p_]

For the iSCSI connection you configured a VMkernel port, therefore you need to use the vmkping command instead of ping. You can do this by logging directly to the console or by ssh/putty.

vmkping 192.168.130.101

vmkping 192.168.131.101

vmkping 192.168.130.102

vmkping 192.168.131.102

Are the ports on the physical switch all configured with the same settings? From what you said, it looks like one of the physical ports is not set up correctly. You could try disabling one of the uplinks on the vSwitch in question at a time. This way the traffic would fail over to the other uplink.

André

[fafa24]

Thank you André

Very helpful answer - I didn't know the vmkping command.

You are right, I can't ping the 192.168.131 network from the server 2 except their own inteface.

I looked careful at the physical switch port and I couldn't see a difference to the other ports, which are working. However on the ports were the 192.168.131 is connected there is no traffic using Rmon statistics. There was some traffic before, perhaps when it was working.

What bothers me, is that it was working a few days before I applied rollup 2 for the server. Of course I have no idea, if it's related or not.

I guess the next steps are to change network cord or use different switch plugs.

Thanks

Edy

[fafa24]

Today I changed plugs at the physical switch and even change network ports on the server for vSwitch1 and vSwitch2.

The result was that the cables I used for vSwtich2 were working with vSwitch1.

I have now the impression that my MD3000i Box refused traffic from vSwitch2 or vSwitch2 isn't working at all.

I believe i can rule out any hardware probleme like faulty network cords or misconfigured physical switch ports.

It could also be a Firwall misconfiguration for vSwitch2

I thought I should reinstall ESX on this server, but I'm unsure if that would help at all.

Hoping somebody might have an idea.

Thanks

Edy

[fafa24]

Dear all,

This issue is now resolved. It was not a problem with physical switch or network cables nor any misconfiguration.

I believe it was a problem with some glitches of the vSwitch2 configuration. I changed the IPs to an other number in the same network and then it worked and my iSCSI box sees now all 4 paths.

Regards

Edy