Instruction manual

CHAPTER 8. SYSTEM BACKUP FOR DEFINITY G3r
CHAPTER 8. SYSTEM BACKUP FOR DEFINITY G3r
Overview
The DEFINITY G3r Mass Storage System (MSS) utilizes tape and disk to provide stable storage
of switch data. MSS configurations include single Switch Processing Element (SPE) and dupli-
cated systems. There are four basic MSS configurations:
Simplex Tape-Only
In a simplex tape-only system, the tape drive
is the primary MSS device.
In this configuration, there is no alternate means to boot the system or
save system data if the tape drive fails.
Simplex Disk/Tape In a simplex disk-tape system, the disk drive is the primary MSS device
and the tape is the secondary MSS device. If the disk is not available,
the tape is available to boot from or to save system data. The tape unit
is normally a backup of the disk In addition, a tape provides a remov-
able backup of the system data.
Duplex Tape-Only In a duplicated processor system, MSS is provided for each processor.
Each processor boots from its local tape unit only. Translation data and
the integrated announcement board data can be backed up from
memory to the local tape unit, the standby tape unit, or both tape units.
Normally, when data is written, both the active and standby tape units
are updated simultaneously.
In addition, scheduled maintenance is provided to verify that the file sys-
tems on each storage device are consistent and that the files are con-
sistent between the different storage devices.
Duplex Disk/Tape
In a duplicated processor system, each processor normally boots from
its local disk unit only. Data is backed up from memory to the local disk,
the local tape unit, the standby disk unit, the standby tape unit, both disk
units, or both tape units. Normally, when data is written, both the active
and standby disk units are updated simultaneously.
Backup from disk to tape can occur on the active system, the standby
system, or on both simultaneously. Restore from tape to disk can occur
on the active system, the standby system, or on both simultaneously.
The primary backup operations are:
● Save translation: All translation data is kept in memory during system operation. This
means that all data would be lost if the switch went down. The save translation operation
allows the System Manager to save the in-memory translation data on disk/tape. This
operation maybe done as part of scheduled maintenance and/or as required.
●
Backup/Restore: In a disk/tape configuration, additional data integrity is achievable
through the disk-to-tape backup process. The backup operation can be done as part of
scheduled maintenance and/or as required. The contents of the disk will be copied onto
a tape. This tape backup contains enough formatting/structure to allow the system to
boot from it.
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