TMF Reference Manual (G06.26+)

TMFCOM Commands
HP NonStop TMF Reference Manual—522418-003
3-157
DUMP FILES
Either of the following strategies, or some combination of both, effectively protects your
databases:
•
To protect specifically against media failures, request online dumps by volume.
•
To protect specifically against damage to a selected application, request online
dumps of the database that belongs to that application.
If an online dump fails before all of the specified audited files are dumped, the amount
of the dump that has completed successfully is saved. In most cases, the TMP
automatically determines the last file that was successfully dumped and implicitly
reissues the DUMP FILES command with the START option specifying the file at which
the dump is to resume. In other cases, however, you might have to perform this restart
yourself, as follows:
•
Use the INFO DUMPS command to determine the last file that was successfully
dumped.
•
Issue a new DUMP FILES command with the START option, specifying the file on
which the dump is to resume.
To avoid dumping your entire database by mistake, use a fully qualified file name for
start-file in the START parameter of the DUMP FILES command.
Online Dumps to Disk
Online dumps can span disk volumes. These dumps are recorded in large files, called
“disk dump files,” on the disks that are specified with the DISKMEDIA option. There
must be enough cumulative space available on all of the specified disks to hold the
online dumps.
For maximum protection, store your online dumps on disks other than those containing
the files being dumped.
Store different generations of online dumps on different sets of disks.
When the disk specified with the DISKMEDIA option is on a remote node, volume
must not exceed seven characters, counting the leading dollar sign ($).
If online dumps are recorded on nonmirrored disks, the RETAINDEPTH option of the
ALTER CATALOG command should be set greater than 1 so that file recovery is still
possible even if one of the disks cannot be read because of a media failure.
Caution. Error messages generated by TMF and other subsystems during online dump
operations can sometimes have a vital impact that is not always obvious. For example, a disk
or tape parity or checksum error can prevent a file from being dumped. For this reason, you
should check the individual messages and summary information displayed by the DUMP
FILES command to ensure that you are aware of all such errors. In addition, you can use the
INFO DUMPS
command to verify that all the intended files were dumped.