System Debug Reference Manual (32650-90888)

Chapter 5 177
System Debug Command Specifications Fx-LOG
GETDUMP
Syntax
GETDUMP dumpfile [ ldevlist ]
GETDUMP dumpfile [ DIR ]
This command is used to restore the contents of a tape created by the DUMP utility onto
disk. Once restored, the dump must be opened by the OPENDUMP command for access by the
DAT program. A tape request for
dumptape is generated; a message appears on the system
console informing the operator of the request.
In order to conserve the disk space used to store a dump, DAT is capable of applying one of
several data compression algorithms to reduce the required storage. Normally, DAT selects
the algorithm which is known to produce the greatest compression, but other algorithms
may be selected based on the setting of the environmental variable GETDUMP_COMP_ALGO.
This variable may be set to a specific algorithm, or to the value "TAPE". This special
setting instructs DAT to use the same algorithm used by DUMP when the tape was
produced. While this setting may not result in minimal disk space consumption, it will
optimize GETDUMP performance, since the dump tape data will never have to be
recompressed with a different algorithm.
Before data on a dump tape are copied to disk, DAT will preallocate a certain amount of
disk space in order to avoid running out of this resource in the middle of a GETDUMP. The
amount of space preallocated is controlled by the environmental variables DUMPALLOC_RLE
and DUMPALLOC_LZ. One of these two variables will be used depending on the data
compression algorithm applied to the dump disk file.
See the ENV command for further information about the environmental variables
mentioned above.
Parameters
dumpfile The name of the dump file to be created. Dump file names are limited to a
maximum of five characters. All files related to the dump are given names
composed of this name followed by a three-character mnemonic indicating
the file contents.
ldevlist A list of secondary-store LDEVs to be read from the dump. If no list is
given, all LDEVs on the dump are read.
DIR This option indicates that only the dump tape directory should be read and
displayed, along with an estimate of the amount of disk space required to
restore the dump. However, the dump itself is not restored. The use of the
DIR option requires a dummy file parameter to be supplied, even though
no disk files are created.
Examples
$nmdat > getdump examp dir
Please mount dump volume #1.
SA 2559 on KC (8/29/88 9:40)
Tape created by SOFTDUMP 99999X A.00.00
MPE-XL A.11.10 dumped on MON, AUG 29, 1988, 9:39 AM