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Re: ISCSI Connection Failure Causing ESXi 5.1 VMs to shutdown

Thanks Don,

FYI, DELL support came back to me after reviewing the logs of our EQL and switches. They said the Equallogic looked fine as it is presenting itself to the hosts. However they think there is a loop in our network as the switch logs are flooded with these messages

<189> JUL 26 08:10:04 192.168.42.48-1 TRAPMGR[151077744]: traputil.c(611) 647 %% 2/0/1 is transitioned from the Forwarding state to the Blocking state in instance 0

<189> JUL 26 08:10:04 192.168.42.48-1 TRAPMGR[151077744]: traputil.c(611) 648 %% 2/0/2 is transitioned from the Forwarding state to the Blocking state in instance 0

We don't have a network engineer as we're a small IT team but I'm assuming if there is a loop, then the switches could be over used and rejecting the iSCSI traffic.

I don't know much about the switch configuration other than what the engineer sent through after the configuration was completed. I'm going to re-check the cabling set up and also read through the iSCSI optimization whitepaper for DELLPowerconnect switches to make sure everything looks ok.

Thanks.

Lee

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Re: ISCSI Connection Failure Causing ESXi 5.1 VMs to shutdown

A loop is alot worse than that.  A "loop" can totally mess up a network.  The switch uses the MAC address table to route packets to the correct port.  If you "loop" the switch, MAC addresses will incorrectly show up at that looped port.  So packets will go there instead.  

That's why when you have multiple cables interconnecting switches, you have to trunk them together.  Otherwise you could loop those switches.  

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8 Krypton

Re: ISCSI Connection Failure Causing ESXi 5.1 VMs to shutdown

Hi,

The EQL engineer spoke to the networks team and they advised the items in the log out are out of date (somehow missed the timestamp) so not to be concerned about.

He says after going over the logs the network config actually looks good and that we should check on the host side. Ensure mem is configured and in use etc. Unfortunately we don't have an enterprise license so have to use native round robin.

I'm following up with VMware now to see if they can shed any light on this.

Thanks for the advice on this issue.

Lee

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Re: ISCSI Connection Failure Causing ESXi 5.1 VMs to shutdown

In the links to other forum posts, that Joe included is a script that will optimze the VMware Round Robin IOs per path setting.  The default is 1000, so until 1000 IOs are sent, it won't switch to another path.  This basically has the effect of the same as FIXED pathing.  We suggest changing it to 3 instead.  So more IOs will actually be in flight at one time.

Regards,

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8 Krypton

Re: ISCSI Connection Failure Causing ESXi 5.1 VMs to shutdown

Great, thanks for the info, I'll have a read and change the setting. Great tip!

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8 Krypton

Re: ISCSI Connection Failure Causing ESXi 5.1 VMs to shutdown

Just thought I'd post an update on this thread for anyone else that has experience this issue. VMware have advised the issue we are seeing is related to a known issue with the tg3 driver.

See this KB for more info: kb.vmware.com/.../search.dolanguage=en_US&cmd=displayKC&externalId=2035701

Thanks

Lee

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Re: ISCSI Connection Failure Causing ESXi 5.1 VMs to shutdown

Thank you.   FYI: That link didn't work for me.   In case anyone else has issues, I used this one:

kb.vmware.com/.../2035701

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