Ensuring Integrity When Sharing DASD Under z/VM › Serializing Access Through Real Reserve/Release Processing › Determining Whether z/VM is Sending Reserve CCWs to Devices

Determining Whether z/VM is Sending Reserve CCWs to Devices

To see if z/VM is sending reserve CCWs to a certain device, specify that device address as a parameter on the QUERY command. For example, to see if z/VM is sending reserve CCWs to device 123, issue this Class B command:

Q 123

To see if z/VM is sending reserve CCWs to any devices, issue this command instead:

Q DASD

If SHARED or DED is specified to the right of the volume label in the resulting display, z/VM is sending reserve CCWs to the device. Otherwise, z/VM is removing reserve CCWs, which means that integrity cannot be ensured among real processors.