Installation guide

the size of the LSM configuration database for each disk group as well
as reduce the amount of overhead incurred in configuration changes.
• If a system will be unavailable for a prolonged amount of time due to a
hardware failure, you can move the physical disks in a disk group to
another system. This is possible because each disk group has a
self-describing LSM configuration database.
All systems with LSM installed have the rootdg disk group. By default,
operations are directed to this disk group. Most systems do not need to use
more than one disk group.
_______________________ Note _______________________
You do not have to add disks to disk groups when a disk is
initialized; disks can be initialized and kept on standby as
replacements for failed disks. Use a disk that is initialized but
has not been added to a disk group to immediately replace a
failing disk in any disk group.
Each disk group maintains an LSM configuration database that contains
detailed records and attributes about the existing disks, volumes, plexes,
and subdisks in the disk group.
8.2.5 LSM Configuration Databases
An LSM configuration database contains records describing all the objects
(volumes, plexes, subdisks, disk media names, and disk access names)
being used in a disk group.
Two identical copies of the LSM configuration database are located in the
private region of each disk within a disk group. LSM maintains two
identical copies of the configuration database in case of full or partial disk
failure.
The contents of the rootdg configuration database is slightly different
from that of an ordinary database in that the rootdg configuration
database contains records for disks outside of the rootdg disk group in
addition to the ordinary disk-group configuration information. Specifically,
a rootdg configuration includes disk-access records that define the disks
and disk groups on the system.
The LSM volume daemon, vold, uses the volboot file during startup to
locate copies of the rootdg configuration database. This file may list disks
that contain configuration copies in standard locations, and can also
contain direct pointers to configuration copy locations. The volboot file is
located in /etc/vol.
Administering the Logical Storage Manager 8–9