Pubsets can be mirrored to increase data security. When used in conjunction with the software product SHC-OSD, disk storage systems provide interfaces for the creation of standby pubsets. When an error occurs, the standby pubsets can take over the functions of a failed pubset. As a result, the downtimes are kept as low as possible and the availability of the pubset or system is increased.
Standby pubsets can be created for home and data pubsets. These are referred to as standby home pubset or standby data pubset:
If the home pubset fails, the system is no longer operable and must be restarted with the standby home pubset. The failed home pubset can then be reconstructed.
If a data pubset fails, applications which access this pubset may no longer be operable. Users of this pubset can be enabled to resume processing activities at a certain checkpoint by importing the standby data pubset. If necessary, the failed data pubset can be reconstructed by systems support.
Standby pubsets must not be used if HSMS migration is employed in the system. Migrated data is no longer available if standby pubsets are used!
Command | Meaning |
ACTIVATE-CLONE | Activate clone pair |
RESTART-CLONE-SESSION | Restart clone pair |
RESTORE-FROM-CLONE | Restore unit from clone unit |
SHOW-CLONE-SESSION-STATUS | Display status of clone pairs |
START-CLONE-SESSION | Create clone pair |
STOP-CLONE-SESSION | Delete clone pair |
Table 23: SHC-OSD commands for the mirroring of standby pubsets
In the context of a high-availability concept with multiple disk storage systems at various locations, data pubsets can also be mirrored to the remote disk storage system.
In addition, the Snapset function, which is based on Snap functions of the disk storage systems, can also be used to generate pubset copies for backup purposes.
For information on Snapsets see section "Data saving using Snapsets".For information on replication functions of external disk storage systems see the “SHC-OSD” manual [48].