A proxy VM may become inaccessible during hotadd backup

‘Hotadd’ backup proxy virtual machine becomes inaccessible or powered off with the following possible symptoms:

1.            Virtual machine randomly stops responding.
2.            When guest operating system fails, there is no BSOD or kernel panic.
3.            The vmx process of virtual machine fails or is killed by ESXi hypervisior with signal 15.
4.            The issue is usually observed during intensive I/O  like backup or operations on database.
5.            In the proxy VM vmware.log file you see entries similar to:
YYYY-MM-DDT01:26:42Z[+2812.868]| vmx| W110: Caught signal 15 -- tid 8554826 (eip 0x1652538f)

This issue occurs due to a race condition in ESXi 5.1/5.5 hypervisor when using a paravirtual SCSI adapter.

You may experience the aforementioned symptoms when using this combination:
1.            HP hardware
2.            HBA Emulex lpfc drivers
3.            ESXi5.1 / ESXi5.5
4.            Paravirtual SCSI adapter

As a workaround, do not use paravirtual SCSI controllers, upgrade ESXi to latest patch version.

Related KB at vmware.com http://kb.vmware.com/kb/2088157