I noticed UCS Manager got unexpected failover after we upgraded firmware to 2.2(2c). Looks like it hits a bug CSCuo11700. Firmware should be upgraded to 2.2.(3a) to fix the issue.
Again something wrong on ESXi 5.5! Please don’t upgrade VMware Tools to 5.5 if you have Debian or Red Hat Linux virtual machine on your ESXi 5.5 hosts. There is a unsolved bug on vmmemctl drivers (balloon driver) of VMware Tools 5.5 can lead to Linux virtual machine hangs.
Few weeks ago, our database virtual machines got randomly failed. There was error message “The CPU has been disabled by the guest operating system. Power off or reset the virtual machine.” on VM events. I didn’t find any abnormal on vmkernel, hostd and vm logs. Finally our Linux team identified it’s a Linux kernel bug. Please refer to BUG at block/blk-core.c:NNNN! in blk_requeue_request or blk finish_request.
The bug only present on RedHat 6 on ESXi 5.5 with VMware Paravirtual SCSI drivers.