More (weird) iSCSI trouble

jthunderbird

So I understand the concept of iSCSI is not that difficult. That being said, I hate it.

I have a home lab (theoretically pictured below) that applicably consists of 3 Dell PE 2950s, 1 Cisco 3550 and 1 D-Link GB switch.

The 3 PE servers are 2 ESXi hosts and my iSCSI target. I am using Starwind for the iSCSI features and it seems to do the job, however very slowly! I have my img file built and the target configured and attached to the img file on the server side.

I configure a new vmk port on its own switch to utilize the 2nd NIC (1st is management, nothing operational yet other than a VM of vCenter). Then dynamically discover and mount the iSCSI target on the storage adapter. Then add new storage on LUN 0 on my 1TB iSCSI on the "Storage" tab. All good. Storage shows up, its usable, seems fine.

The vmk I configure is on a GB port connected to an unmanaged GB D-Link switch that also has a connection from the 2nd NIC on the iSCSI SAN server. Pings transverse over the GB link as they should. But when I attempt to upload a file from the local hard drive of the iSCSI SAN to the actual iSCSI SAN via vCenter, then traffic seems to try and use BOTH management and iSCSI network ports and is slow.

jibbajabba

ISCSI uses vmkernel ports and your management port is a vmkernel port as well.

What you should do is separating management and storage traffic. Use different VLANs / Subnet for both.

Also, on the networking tab of the vSphere ISCSI Initiator you can bind a vmkernel to iscsi .. in order to dedicate a vmkernel for iscsi, it needs to have a single uplink.

You say you have a second switch for iscsi ? I presume you mean virtual switch, so you got two virtual switches, each switch got a single uplink where the first one has the management VMK and the second the ISCSI vmk ?


If that is the case then you should indeed be able to dedicate a VMK for ISCSI



Still, you should use a different VLAN and subnet for iscsi - that way it wouldn't even be able to use the wrong NIC

(Ignore the fact that both are using the same VLAN in my screenshot lol - Only quickly did that for the screenshot showing you can dedicate a VMK)

jthunderbird

Yes by 2nd switch, I meant a new virtual standard switch, my bad on not being more clear there.

I did dedicate the iSCSI vmk port to iSCSI and it didnt change anything. The management port and iSCSI ports are on very different subnets but I was having trouble getting the VLAN assignment to work. Whenever I assigned VLAN 10 to the management port, I lost connectivity... though the correlating Cisco port is in fact on VLAN 10 and VMWare knows this, as CDP could even tell me that the virtual switch saw VLAN 10.

Whenever I changed that management port VLAN, Id lose connectivity and have to console to the ESXi machine UI and change the VLAN back to 0. I cant change the VLAN on the iSCSI because the switch it is using is unmanaged.

jthunderbird

I am wondering if maybe trying to upload a file from the local C: drive of the server to the logical iSCSI drive on the same server is causing some sort of conflict. Wonder if I physically seperate the upload point and the iSCSI SAN, if the issue would resolve itself.

Also, I am behind a military firewall at the moment so cant see your pic. Any chance you could upload it to TE like I attached mine? No worries if not, just cant see exactly what you intended (though I am pretty confident I was able to bind the port to iSCSI correctly last night)

jibbajabba

Do you have access to VLAN 10 ? As in, the server / pc connecting to the hosts on vlan10 need to be in the vlan as well (or at least getting routed) otherwise you won't be able to get to vlan10 - that's the whole definition of vlans really.

You could try using the same VLAN for management and ISCSI, but use different subnets

For example

Management VLAN 0
192.168.1.0/24

ISCSI VLAN 0
192.168.10.0/24

Not ideal or best practise .. But that way ISCSI wouldn't go over the Management NIC as it is a different subnet (assuming your SAN in this case is also on 192.168.10.0/24

jthunderbird

Yes I understand VLANs very well. The ESXi servers and SAN server 1st NIC are all plugged into the Cisco switch on access VLAN 10. But as soon as I change the vlan on the virtual switch, I lose connectivity.

Right now, it is set up how you explained in the bottom. They are both on VLAN 0 but completely different subnets.

jibbajabba

I mean YOUR machine has to be in the same VLAN too .. So if you sit at your laptop and try to connect to a host and change the VLAN, unless your laptop can see the VLAN, you will lose connectivity ... Unless with "I" you mean even the vCenter server (which also needs to see VLAN 10).

JBrown

post your vswitch screenshot here, its better to see it once than hear about it a hundred times.

jthunderbird

JBrown wrote: »

post your vswitch screenshot here, its better to see it once than hear about it a hundred times.

Ok I can do that when I get home. Yes the management PC I am on is also in VLAN 10 but I didnt put the virtual vCenter server in VLAN 10. Didnt think I had to since I never lost connectivity with vCenter (I could still manage my other ESXi host through vCenter).

I will look into it today when I get home and get screenshots and all that if I cant fix the VLAN issue.

jibbajabba

Is your VLAN 10 just for storage ?