/REDUCE-VM-MEMORY is used to reduce the main memory of a VM during the current session. The reconfiguration of the main memory can be monitored with a monitor job variable.
After the main memory reduction, the new main memory size is noted in the VM definition.
The main memory of a VM cannot be reduced while the VM is being migrated (VM Migration).
Main memory reconfiguration is possible for VMs in states INIT-ONLY or DOWN. In the case of active guest systems (VM state RUNNING), main memory reconfiguration is only possible after SYSTEM READY for the guest system. Main memory reconfiguration is not possible for VMs in state IN HOLD (WAIT).
Since dynamic reconfiguration of main memory requires measures to be taken both in the (active) guest system and in VM2000, the process can be time-consuming. The actual main memory reconfiguration takes place asynchronously after the command has been accepted. During this time any further /EXTEND-VM-MEMORY or /REDUCE-VM-MEMORY command for the same VM will be rejected. The /MOVE-VM (SU /390) and /START-VM commands can be executed during main memory reconfiguration. In this case, the previous main memory size is used as the main memory size for the relevant VM. The same applies when the guest system is restarted.
 | On SU x86, aborting a main memory reconfiguration with /START-VM, /RESET-VM or /DELETE-VM should be avoided. Reason: The reconfiguration will only be aborted in BS2000 but continued in the firmware and the carrier system. A BS2000 IPL with /START-VM may be delayed until the reconfiguration in the carrier system is complete. |
This command is reserved for the VM2000 administrator.
REDUCE-VM-MEMORY |
VM-IDENTIFICATION = <integer 1..99> / <name 1..8> ,NEW-MEMORY-SIZE = *MINIMUM / <integer 1..1048576>(DIMENSION = *MEGABYTE / *GIGABYTE) ,MONJV= *NONE / <filename 1..54 without-gen-vers> ,JV-PASSWORD = *NONE / <c-string 1..4> / <x-string 1..8> / <integer -2147483648..2147483647> |
VM-IDENTIFICATION = <integer 1..99> / <name 1..8>
Identifies the virtual machine by means of a VM index or VM name. The monitor VM’s main memory can also be reduced.
NEW-MEMORY-SIZE = *MINIMUM / <integer 1..1048576>(DIMENSION = *MEGABYTE / *GIGABYTE)
New size of main memory after reduction for the relevant VM up to a size of 1 Tbyte
(terabyte; 1 Tbyte = 1024 Gbytes = 1 048 576 Mbytes).
 | On SU /390, the new main memory size may be below the MIN-MEMORY-SIZE of the VM concerned if the VM is in state INIT-ONLY or DOWN. In this case the value for the VM’s MIN-MEMORY-SIZE is assigned the value of NEW-MEMORY-SIZE. |
 | On SU x86, the new main memory size may not be below the MIN-MEMORY-SIZE of the VM concerned. The value must be a multiple of 2 Mbytes. |
If *MINIMUM is specified, the main memory size of the VM will be reduced to the smallest possible main memory size (MIN-MEMORY-SIZE).
MONJV =
Defines a monitor job variable for monitoring the reconfiguration of the main memory (see the corresponding paragraph in section "Reconfiguring main memory").
MONJV = *NONE
No monitor job variable is defined.
MONJV = <filename 1..54 without-gen-vers>
The specified MONJV is supplied with data by VM2000; therefore, the sender of the command must have write permission for the specified MONJV. If no catalog ID or user ID is specified in the file name, VM2000 completes the file name, in accordance with the runtime environment of the sender of the command. If the specified file name does not refer to an existing job variable, VM2000 creates the MONJV as shareable and without a password.
JV-PASSWORD = *NONE / <c-string 1..4> / <x-string 1..8> / <integer ...>
Password of the MONJV for checking access authorization. The input field is automatically blanked in the guided dialog. The value input is not logged.
MONJV.Command return codes
(SC2) | Main code | Meaning |
0 | CMD0001 | Command successfully executed |
Guaranteed messages
VMS2306 (SU /390)
Example
/reduce-vm-memory vm-id=2,new-memory-size=*minimum ————————————————————— (1)/show-vm-resources information=*memory ————————————————————————————————— (2)
VM-ID LOC-BEGIN MEM-SIZE MIN-MEM-S MAX-MEM-S DEST-MEM-SHYPERVISOR 00000000 16 1 MONITOR 00000010 512 512 2 SYSTEM2 00000210 768 512 512NONE 00000510 14576LARGEST FREE DOMAIN: 14576/show-vm-resources information=*memory
VMS4094 MEMORY-RECONFIGURATION FOR VIRTUAL MACHINE (2,SYSTEM2) HAS BEEN SUCCESSFULLY PROCESSED. CURRENT MEMORY SIZES: 512 / 512 ——————— (3)VM-ID LOC-BEGIN MEM-SIZE MIN-MEM-S MAX-MEM-S DEST-MEM-S
HYPERVISOR 00000000 16 1 MONITOR 00000010 512 512 2 SYSTEM2 00000210 512 512 ——————————————————————————— (4) NONE 00000410 14832LARGEST FREE DOMAIN: 14832
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(1) | The main memory for the |
(2) | The VM2000 administrator fetches information on the main memory distribution in VM2000. VM2 has a main memory size of 768 Mbytes and a minimum memory size of 512 Mbytes. The planned new memory size of 512 Mbytes is shown as well while the request is being processed. |
(3) | Completion of the asynchronous reconfiguration request is reported to the VM2000 administrator as an asynchronous (guaranteed) message in the user event stream or displayed at the next input (main memory reconfiguration is time-consuming). |
(4) | The main memory size for VM2 is now 512 Mbytes (again). This increases the remaining free main memory. |