TRACK is probably the BEST all-around tool to have available on your VM system. It has a number of features in to help system programmers diagnose problems or validate the internal workings of VM userids (guests).
Although there are other individual tools to do what TRACK does, TRACK does it all in one package. TRACK examines one or more virtual machines as they execute. It is a full screen program that is PF key driven and displays information in a number of different panels. It shows selected information from the TRACKed user's VMDBK, real and virtual storage, all of a user's devices, details about one device, open console page along with certain information about a CMS user's virtual machine, such as accessed disks, open files, filedefs, etc.
You will need CLASS E to use Diag 004 (read CP real storage) in order to use TRACK. You will also want CLASS A for the CP LOCK command. If you moved these commands to different privileges, adjust accordingly. Note - although you need high privileges, TRACK never modifies storage in any way! TRACK is non-destructive to the target userid.
TRACK has very well documented commands and functions. TRACK MEMO gets you started with the install instructions and other notes of interest on the tool. There are also 34 CMS HELP files included in the package covering both the TRACK command parms and sub-commands available within TRACK. There is also a TRACK MENU file help navigate them all.