ESX host can't see the iscsi lun

[ygao]

Well, we have a netapp fas2020 that I'm testing iSCSI with, at first, everything was fine, both of my HP DL 365 are able to see the iSCSI lun, however, after I reboot one of the ESX server and fixed the clock in the BIOs (it was about 6 month behind), I can't see the lun anymore, I rebooted few times and re add the iSCSI name on the filer, I still can't see the lun.

our Netapp guy said this have something to do with the ESX, any ideas? Thanks in advance.

[Abaronov]

did you do a rescan? It usually helps

thanks,

Andrei

[davesil2]

Check your security profile and make sure the software iscsi client is allowed to access through the firewall.

[davesil2]

actually, if you check the screen on your ESX servers, do you see anything stating that the device is there but with a different signature?

If so you can go to advanced settings, select LVM and change the "LVM.EnableresignatureLun" = 1 and rescan then set it back to 0. This advice is offered without warranty so please be careful if this is a production system.

I've run into this several times and the ScsiID of the volume may have changed, vmware doesn't like that since it know's who is who based on the signature. If the signature was based on time that could account for that.

-David

[ygao]

Well, I tried this, the LUN is still not showing up and there is no FW between my ESX host and Fas2020....Any other ideas? thanks...

[davesil2]

The ESX Server has a "built in" firewall. If the Software iSCSI Client is not enabled, then it cannot connect to the target.

[ygao]

Do you have an command to check that? Thanks.

[davesil2]

esxcfg-firewall --query swISCSIClient

this will list if the iscsi client service is enabled throught the firewal.

As as side note, did you say this did work at one point and the all of a sudden stopped? Or has it never worked in your testing?

-David

[ygao]

Well, it is blocked, but it is also blocked on the 2nd server that is working, should i open it up?

Service swISCSIClient is blocked.

Yes, it was working fine until I rebooted the host to fix the time in the BIOs.

[TECarlton]

I had this issue just this morning. After upgrading two of my prduction ESX 3.0.2 U1 hosts to 3.5.0 I was not able to see my iSCSI san luns. A call to tech support pointed me at the internal firewall setting. From the VI client select the host in question. Goto Configuration then select Security Profile from the options on the left and then Properties at the top right. Make sure that the "Software iSCSI Client" is checked. If not check it, click "OK", and the rescan your iscsi luns and all should be right with the world. Tech support said they'd make a note of this since this setting changed "all by itself" during a standard upgrade... After these two I did the other two and they did the same thing as well.

Cheers!

[ygao]

Dude! You are a life saver!...that is the problem, though mine is a bit

different from yours, I didn't even upgrade, just a reboot....thanks

alot and thank you to Dave too, you provided alot of valualble inputs...thanks again guys...

[davesil2 · Accepted solution]

yes you must have the iscsi client enabled through the esx server firewall, you can use command line or the GUI VIC software to update

[Erik_Bussink]

Another common problem, is that the authentication towards a iSCSI target is done using the Service Console (and it's Physical NIC) and the iSCSI data trafic is going over the VMkernel interface (and i'ts Physical NIC).

We just ran into the problem, where the authentication was going thru, but the physical nic used behind the VMkernelhad VLAN configured by mistake.

[Erik_Bussink]

oops... double post