ADVM Processes

A small number of processes will be added to the ASM instance when a volume is enabled. These processes are not started when there are no volumes configured.

• The Volume Driver Background (VDBG) process forwards ASM requests to lock or unlock an extent for rebalancing, resize the volume, offline the disk, add or drop a disk, and force and dismount a disk group to the dynamic volume manager driver. The VDBG is a fatal background process so the termination of this process brings down the ASM instance.
• Volume Background (VBGn) processes wait for requests from the dynamic volume manager driver that need to be coordinated with the ASM instance. An example of such a request would be opening or closing an ASM volume file when the dynamic volume manager driver receives an open for a volume (possibly due to a file system mount request) or close for an open volume (possibly due to a file system unmount request). The unplanned death of any of these processes does not have an effect on the ASM instance.
• Volume Membership Background (VMB) coordinates cluster membership with the ASM instance.