Parameter
vmcj/vm_auto_restart
Short text
Automatic VM restart
Parameter Description
This parameter specifies whether a VM is to be stopped automatically. This can be useful to temporarily correct errors (such as memory leaks). The VM is restarted either once a set time limit has been exceeded or if the “old generation” occupation of the Java heap has exceeded a set limit value.
Furthermore, you can configure with the parameter whether VMs that have to contribute to a shared garbage collection (SGC) and are currently in the pool have to be stopped. This parameter only takes effect if VM cloning is active (see parameter vmcj/cloning ). With large data sets the SGS takes longer. This is why stopping and renewing cloning of a VM can improve performance in such situations.
However, you should only set the parameter if SAP recommends that you do so.
Application Area
VMC
Parameter Unit
Syntax
vmcj/vm_auto_restart = [Grund]* | [Grund] , [Grund]* [Grund] = [[Zeitwert]] | [[OldGen-Limit]] | [BEFORE_SGC] [Zeitwert] = TIME=[Zahl] [ H|M] [OldGen-Limit] = OLD_GEN=[Zahl]
You can specify the time value with or without a time unit. If you do not specify a time unit, seconds is used as the unit. Otherwise M can be specified for minute or H for hour. There can be spaces between the value and the unit. The value 0 means that the VM should not be restarted on the basis of a time interval.
The OldGen limit is a percentage between 0 and 100 %.
Examples
OLD_GEN=95 -> Stop VM if more than 95% of the old generation is reserved
TIME=1H -> Stop VM if the VM is older than one hour
TIME=1H, OLD_GEN=90 -> Stop VM if the VM is older than one hour or if more than 90% of the old generation is reserved.
BEFORE_SGC -> Stop VM if the VM is in the pool, has to contribute to an SGC, and VM cloning is active.
The value 0% means that no VM is to be stopped based on reservation of the old generation.
Default Value
Empty (no VM is automatically stopped)
Who is permitted to make changes?
Customer with SAP support
Operating System Restrictions
None
Database System Restrictions
None
Are other parameters affected or dependent?
None
Values allowed
Character string
