install_path:\Program Files\VERITAS\NetBackup\logs\bpsynth
also check bpdpm
Logs produced during synthetic backups
When a synthetic backup is scheduled, NetBackup starts the bpsynth program to
manage the synthetic backup process. bpsynth plans how the synthetic backup
is built from the previous backup images.
If it is needed, bpsynth then schedules the tape drive resources that are needed
for the synthetic backup. If the required resources are not available, the job fails
with a status code that indicates that a resource is needed.
If the resources can be obtained eventually but not immediately, the synthetic
job waits until the resources become available. A synthetic job may wait while a
backup, restore, or another synthetic backup job uses a drive.
bpsynth passes the information to programs bptm and bpdm so that tape and disk
images can be read or written. Catalog information is managed using bpdbm. Each
of these programs has a debug log file in the logs directory.
If problems occur with synthetic backups, the following debug logs are required
to diagnose the problem:
■ On the master server: bpsynth, bpdbm, and the log files located in
install_path:\Program Files\VERITAS\NetBackup\logs
as described in the NetBackup Troubleshooting Guide.
■ On the media server(s): bptm (if any tape images), bpdm (if any disk images),
bpcd
Note that several media servers can be involved if the component images are
on different nodes.
However, bpsynth is used for each stream or client. To use bpsynth can be
inefficient with tape images since bpsynth needs a tape drive to write the new
image. Also, bpsynth may use the same component image volumes. One may need
to finish before the next can proceed.
Taken from Netbackup admin guide