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The VIR2REAL EXEC calculates and displays the ratio of the total amount of virtual storage (memory) of all logged on users to the real storage of your running VM system. A system with storage ratio that is too large may experience excessive paging rates or other performance problems because the real memory is overcomitted. A system with a small ratio (less than or near 1) that has sufficient CPU capacity available should be able to handle more workload. This exec just shows the current ratio for the userids that are active on the system at the time the exec is run. For tracking the ratio over time, you should obtain and use a performance monitor product.

The exec operates by finding all logged on users using QUERY NAMES. It gets each user's storage size and how it was started (IPL) using INDICATE USER and adds up all of the numbers. It gets the real storage size using the QUERY STORAGE, QUERY XSTORAGE, and QUERY FRAMES commands. Then, it displays the virtual storage totals and a total for all userids that use a defined list of NSS names to IPL. It also shows the real storage totals and the ratio of the virtual totals to the real total storage. In addition, it also queries the number of VDISKs (virtual disk in storage) defined using the QUERY VDISK command, and queries the amount of paging space and its utilization using the QUERY ALLOC command. This information is also displayed.

Note: The exec must be run on a userid with sufficient CP privileges. The minimum default IBM privileges are B and E. It uses the CP commands QUERY STORAGE, QUERY FRAMES, and QUERY XSTORAGE to obtain real storage values and INDICATE USER userid to obtain the virtual storage values. If the QUERY VDISK command is available, it will also show information about vdisks. And if the command QUERY ALLOC is available, it will show the amount of page space and its utilization.

An example of the output from VIR2REAL, with footnotes:

Storage information for VM system PTCVMD01
Any userid using NSSes "CMS GCS" are considered CMS users.1

Total Virtual storage (only ids not running CMS):  205312 MB (  200.5 GB)2
Total Virtual storage (only ids running CMS):        1104 MB (    1.1 GB)3
Total Virtual storage (all logged on userids):     206416 MB (  201.6 GB)
Usable real storage (pageable) for this system:     81127 MB (   79.2 GB)4
Total LPAR Real storage:                            81920 MB (   80.0 GB)
Expanded storage usable for paging:                  2048 MB (    2.0 GB)5

Total Virtual disk (VDISK) space defined:           43256 MB (   42.2 GB)
Average Virtual disk size:                            158 MB

Virtual to (usable) Real storage ratio:     2.5 : 16
Virtual + VDISK to Real storage ratio:      3.1 : 17
Virtual to Real ratio (non CMS work only):  2.5 : 18

Paging:  78 volumes defined, total space is:       183072 MB (  178.8 GB)
Total Paging space in use (25% utilization):        46188 MB (   45.1 GB)


Notes about the output:

1. This line lists the NSS names active on the system that are considered to be CMS users. The search values are defined in the exec and can be changed if desired.
2. The total virtual storage of all users except those running systems with NSS names shown in the previous output line.
3. The total virtual storage of all the NSS users.
4. The amount of storage that is available for running virtual machines. It is less than the total storage available on the LPAR because the CP nucleus and other control blocks are fixed in storage.
5. This be less than the amount of expanded storage defined to the LPAR if some of it is dedicated to users
6. The ratio of all virtual storage to the real storage.
7. The ratio of all virtual storage plus all defined VDISKS to the real storage.
8. The ratio of the storage of all active users' that are not running CMS to the real storage.

Feedback: Bruce Hayden IBM Advanced Technical Support