I upgraded my ESXi 5.1 U1 to ESXi 5.1 U2 using SSH, after upgrade complete and I restart the server I couldn't connect to the Server using vSphere Client but I could connect to it using SSH after few Hours also the SSH stop working but all of my VMs work correctly.
I Tried to restart the server but the situation repeat I'm unable to connect using vSphere Client and Just for few Hours I can use SSH.
Because the server located in a data center I have limited access to my Server Screen and Keyboard (it is possible but have cost).
Part of vmkernel.log is:
2014-02-24T23:45:01.296Z cpu5:521314)ALERT: hostd detected to be non-responsive 2014-02-24T23:50:01.297Z cpu1:521473)WARNING: Tcpip: 1304: socreate(type=2, proto=0) failed with error No buffer space available (55) 2014-02-24T23:52:07.996Z cpu2:519491)WARNING: LinScsi: SCSILinuxQueueCommand:1193:queuecommand failed with status = 0x1056 Unknown status vmhba33:0:0:0 (driver name: ahci) - Message repeated 2194 times 2014-02-24T23:52:09.421Z cpu0:6262)ScsiDeviceIO: 2318: Cmd(0x4124007a2140) 0x2a, CmdSN 0x800000e4 from world 6549 to dev "t10.ATA_____TOSH IBA_DT01ACA300_________________________________33815YEAS" failed H:0x0 D:0x8 P:0x0 Possible sense data: 0x0 0x0 0x0.