RDF System Management Manual

Managing RDF
HP NonStop RDF System Management Manual—524388-003
5-33
Making Online Dumps With Updaters Running
For a successful backup, follow these steps:
1. Execute a process that opens the image trail file with shared read access. This can
be a simple process that you supply to perform only this operation. When the
purger determines that all updaters are finished with this image trail file (named,
say, AA000007), and have moved on to the next image trail file (named, say,
AA000008), then it may try to purge AA000007. The purge operation will fail,
however, because your process still has AA000007 open. The purger will terminate
the purge attempt and try it again later. As long as your process keeps AA000007
open, the purger cannot purge it.
2. When the purger tries to purge AA000007 and fails, it writes a message denoting
this error to the EMS event log. This message implies that all updaters have
moved from AA000007 to AA000008 (or beyond), and will never need AA000007
again; it is your only way to know for certain that AA000007 will never be needed
again. When this message is written, you can start the backup process to dump
AA000007 to tape.
3. When the backup process opens AA000007 and the backup is in progress, you
can stop the file-opening process run in Step 1. The purger will continue its
attempts to purge AA000007, but these attempts also will fail as long as the
backup process has AA000007 open. Eventually, when the backup is complete
and AA000007 is successfully copied to tape, no processes will have this file open.
After this point, the purger will be able to purge AA000007 successfully.
Repeat the preceding steps for each image trail file you wish to back up.
Making Online Dumps With Updaters Running
RDF/IMP, IMPX, and ZLT allow you to take dumps of the backup database while the
updaters are running. To do this, you use the UPDATEROPEN parameter of a SET
RDF or ALTER RDF command to specify the access mode (protected or shared) that
all of the updaters use when opening database files.
The default is protected access.
Protected access is strongly recommended, except when you specifically wish to take
dumps of the backup database with the updaters running.
To take online dumps of the backup database while the updaters are running, do as
follows:
1. Stop the updaters (issue a STOP UPDATE command on the primary system).
2. Alter the UPDATEROPEN attribute of the RDF configuration to SHARED:
ALTER RDF UPDATEROPEN SHARED
3. Restart the updaters (issue a START UPDATE command on the primary system).
4. Initiate the online dump.