I recently faced a problem when our backup administrator was unable to browse remotely the root (/) file system on Solaris when the system was installed as a guest in a VMware ESX hypervisor. After digging around the system, I find that the Host-Guest File System made the HP DataProtector agent unable to stat the /hgfs pseudo-file system as can be seen in the /var/opt/omni/log/debug.log debug log file:

[...]
09/23/10 17:06:36  FSBRDA.11618.0 ["da/bda/solaris.c /main/blr_dp61/10":1324] A.06.11 b243
SolStatObj: /hgfs lstat failed! errno 5

Although it is not a bug per itself, installing the VMware Tools just enable the HGFS module independently of the virtualization stack: VMware ESX doesn't provide access to the Shared Folders facility, although the VMware Workstation does. So in my case, I can just disable it without loosing any useful functionality.

Since it may be advisable to have a configuration option at the VMware Tools level, I didn't find one. Some may argue that write a little script at the boot to unmount the /hgfs file system is good enough, I find painful and not very elegant. In fact, I prefer to disable at the kernel module level using the module's configuration file:

# cp -p /kernel/drv/vmhgfs.conf /kernel/drv/vmhgfs.conf.orig
/* Edit, and comment the vmhgfs line. */
# cat /kernel/drv/vmhgfs.conf
# name= parent="pseudo" instance=0;
#name="vmhgfs" parent="pseudo" instance=0;

Last, be sure to recreate the GRUB boot archive before rebooting the system, and all backup stuff went well again.

# bootadm update-archive
# shutdown -y -i 6 -g 0