I have a strange problem. Our esxi hosts keep logging in and out of our 10GbE targets on our SAN (Nexsan E18). I've been working with Nexsan support and VMWare but everything seems in order. jumbo frames are enabled, switch settings are correct, mtu settings on the vswitch and portgroups are set correctly. Everything is working and we can see the datastores but the constant login and logout sometimes locks up the 10GbE ports. We have:
Power Connect 5524 switch
10GbE ports on the 5524 connected to the NexSan
esxi hosts 4.1
jumbo frames enabled on the Nexsan and the esxi hosts
esxi hosts are connected via 1GB
the powerconnect 5524 is only handling the iscsi traffic. its completely separate from our data and voip traffic.
nexsan support sees around 13 login/logouts in the space of 2 minutes. when connecting the 1GB iscsi port on the nexsan we do not see this behavior. unfortunately i dont have another switch with 10GbE ports to test. I can vmkping -s 8000 to the 10GbE ports but not 9000. VMWare told me to set the mtu on the switch to something above 9000. Dell told me that when you "iscsi enable" on the switch it already sets the mtu to 9216. I have a netapp (connected to 1GB iscsi) and i can vmkping with 9000.
Has anyone else come across anything like this?