Automatic restart of z/OS
The purpose of automatic restart is to reduce the amount of time that a particular system is down.
When Db2 or IRLM stops abnormally, the surviving z/OS® systems analyze the situation to determine whether z/OS failed too, and where Db2 or IRLM should be restarted. If z/OS did not fail, then Db2 or IRLM is restarted on the same z/OS image. If z/OS failed, then Db2 or IRLM is restarted on another z/OS image.
Automatic Restart Manager (ARM) is the component of z/OS that manages automatic restarts.