HP NonStop G-Series - Manual (Page 28)

Introduction to Storage Management
HP NonStop Storage Management Foundation User's Guide—523562-008
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Overview of SMF Processes
Overview of SMF Processes
There are three main types of SMF processes: the master process, pool processes,
and virtual disk processes. All three are multithreaded process pairs, configured by
system tools and started at system start-up time.
Master Process
The SMF master process manages a centrally located database of information
required at start-up time for all other SMF processes. The master process coordinates
SMF configuration and modification for storage pools and virtual disks.
The master process name, $ZSMS, is a fixed name.
Pool Processes
Pool processes are responsible for collecting and distributing information about
physical volumes associated with a pool to the virtual disks that use its storage. A pool
process executes as a process pair whose process name is the name of the storage
pool. Pool processes notify virtual disk processes when the status or configuration of
physical disks in the storage pool changes; for example, if new disks are added to the
pool, or if a physical disk becomes unavailable.
Pool processes also keep statistical information about the volumes in a pool and
convey this information to the virtual disk processes when requested. Virtual disk
processes use this information to select physical volumes when creating files. Finally,
Figure 1-1. Relationships of Virtual Disks to Physical Volumes in a Storage Pool
001 CDT .CDD
Physical
Volumes
Virtual
Disk
Storage Pool
Virtual
Disk