Instruction manual
CHAPTER 8. SYSTEM BACKUP FOR DEFINITY G3r
Backup Command
Additional data integrity is achievable through disk to tape backups. These backups may be
done on demand or run daily as part of scheduled maintenance. This command is only valid in a
system which has both disk and tape as part of its MSS. The
backup
command will work in
either a simplex SPE or a duplex SPE system. When the command is run as part of scheduled
maintenance, the default for a simplex system is an
incremental
backup of SPE A. In a duplex
system, the default is an
incremental
backup on
both
SPE
A
and SPE B.
When the
backup
command is executed on demand the defaults remain the same.
Command Syntax
backup disk [active | standby | SPE_A | SPE_B | both | either] [incremental | full]
The bracketed options,
[active | standby | SPE_A | SPE_B | both | either],
specify which mass
storage system the user wishes to backup. Invoking the backup command with the
SPE_A
option causes files from the disk associated with processor
A
to be copied to the tape cartridge
on the same processor.
SPE_A
is the default in a simplex system. Invoking the backup com-
mand with the
SPE_B
option causes the files on the disk on
processor
B
to be copied to the tape
on the same processor.
Invoking the command with the
active
option causes the files on the disk on the active processor
to be copied to the tape on that processor.
Invoking the command with the
standby
option causes the files on the disk on the standby pro-
cessor to be copied to the tape on that processor.
Invoking the
backup
command with the
both
option causes files on the disk associated with
both of the processors to be backed up to their respective tapes concurrently. If the standby pro-
cessor is inaccessible the command will fail on both processors. No files will be copied from disk
to tape on either processor. The default value in a duplex system is
both.
Invoking the
backup disk
command with the
either
option causes the files on the disks associ-
ated with both of the processors to be backed up to their respective tapes concurrently. If the
standby processor is inaccessible, the command will still execute on the active processor and the
disk files will be copied to tape.
Invoking the command with the
incremental
option causes a selective backup to be performed.
In this case, all files on the disk that are marked as “good files” and which have a newer last file
update time than the corresponding tape files, are copied to the tape. Not copying files marked
as “bad” ensures that corrupted files do not overwrite good (but possibly older) files. The default
value is
incremental.
If a
full
disk backup is specified, the entire disk is copied to tape. All files, “good” and “bad,”
regardless of the last file update times, will be copied to the tape.
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