Specifications

www.vmware.com
194
VMware GSX Server Administration Guide
Enabling SCSI Reservation
SCSI reservation must be enabled in a virtual machine before you can share its disks.
To enable SCSI reservation, make sure the virtual machine is powered off. Open the
configuration file (.vmx) in a text editor and add the line:
scsi<n>.sharedBus = "virtual"
anywhere in the file, where <n> is the SCSI bus (controller) being shared.
VMware recommends you set up the shared disks on their own SCSI bus, which is a
different bus than the one the guest operating system uses. For example, if your guest
operating system is on the scsi0 bus, you should set up disks to share on the
scsi1 or scsi2 bus.
To enable SCSI reservation for devices on the scsi1 bus, add the following line to
the virtual machine’s configuration file:
scsi1.sharedBus = "virtual"
This allows the whole bus to be shared and is quicker than specifying each disk
separately. However, if you do not want to share the whole bus, you can selectively
enable SCSI reservation for a specific SCSI disk on the shared bus. This prevents the
locking of that disk. Add the following line to the configuration file:
scsi1:1.shared = "true"
If SCSI reservation is enabled (that is, scsi1.sharedBus is set to "virtual"),
then this setting is ignored.
In addition to enabling SCSI reservation on the bus, you need to allow virtual
machines to access the shared disk concurrently. Add the following line to the virtual
machine’s configuration file:
disk.locking = "false"
This setting permits multiple virtual machines to access a disk concurrently. Be careful
though: if any virtual machine not configured for SCSI reservation tries to access this
disk concurrently, then the shared disk is vulnerable to corruption or data loss.
Caution: This setting applies to all SCSI devices in the virtual machine.
When SCSI reservation is enabled, the system creates a reservation lock file that
contains the shared state of the reservation for the given disk. The name of this file
consists of the filename of the SCSI disk appended with .RESLCK.