Datastore missing after attempting to configure jumbo frames

[ahcomput]

I was attempting to configure my iSCSI network to use jumbo frames.  I enabled this feature on the switch and ran these commands from cli to configure in vsphere:

esxcfg-vmknic -m 9000 iSCSI

when I ran esxcfg-vmknic -l, it shows 9000 mtu in vmk2 iSCSI

esxcfg-vswitch -l shows switch name vSwitch1 is set to 9000 mtu

I successfully ping my iscsi storage ip with a payload of 8000 by running:

ping 192.168.30.9 -d -s 8000 and getting replies

However, when i launch vsphere client, my two vm's show "Unkown (inaccessible)".  When I go to configuration > storage, by datastore is missing.  When I refresh it still doesn't show.

As you may notice, I'm new to vmware and would appreciate any guidance to get my datastore back.

-Ben

[SuryaVMware]

What is the Storage Array? Have you configured/enabled JF on the Storage controller? Also do you have vLAN configured on the switches?

-Surya

[ahcomput]

Switches are dedicated to iscsi. I'm using a DROBO "elite" and they are configured for JF. I can ping them successfully with an 8000 payload.

Sent from my iPhone, so please pardon shorthand, spelling, and poor grammar.

[BradI100]

Have you gone into your host hardware settings > storage and refreshed storage?  I've tested Jumbo Frames on this Unit and even if you misconfigure it, I think you should still see the LUNs.  You may also need to go into Storage adapters and "Properties" and make sure your targets are correct.

BTW, what kind of performance did you get while using 1500 MTU?  I can run maybe 1 server (slowly) but add another and the Drobo crashes when you least expect it..

[ahcomput]

I ended up reverting back to 1500 until I can get my Jumbo Frames configuration resolved.

I have had MANY problems w/ DROB "Elite".  I found the performance has been horrible.  When I was just running one VM on it, it was ok, but now that I have added an additional volume as a backup target (disk to disk from appassure) I find it regularly becomes unresponive.  I can ping and get replies but the drives will disappear from my servers and the dasboard can't locate it until I restart drobo.

Did you find your performance improved by using Jumbo Frames?

[BradI100]

No, unfortunately, Jumbo frames didn't do anything for performance.  What makes this unit tough to deal with is it runs very well with 1-2 guests.  But then add a third and it can lock up.    You've undoubtedly compared CPU, Memory and HDD activity for the trouble times and come up empty handed as have I.   Just a guess, but I think it has trouble handling more the overhead of multiple connections than providing adequate iops and MBps.  YMMV