If you use a file-oriented backup program, you might want
to exclude some subdirectories within the VOB storage directory to
save time. Use the guidelines in
Table 1 to determine
the relative importance of the various directories.
Table 1. Importance of VOB directories in partial
backups| VOB directory |
Importance for backup |
|---|
| Top-level VOB storage directory |
Required |
| VOB database subdirectory |
Required |
| Source storage pools |
Required |
| Derived object storage pools |
Important, but not required. |
| Cleartext storage pools |
Optional |
| Administrative directory |
Optional |
DO pool backup
Derived
object storage pools do not exist unless you use the MVFS and programs
such as
clearmake,
omake, or
clearaudit.
Backing up derived object storage pools is not required because, by
definition, DOs can be rebuilt from sources. The importance of backing
up these pools might change over time:
- In the early stages of a project, when the source base is changing
rapidly, the useful life of most derived objects is very short. Omitting
DO storage pools from a backup regimen at this stage should not cause
a problem.
- When a project is relatively stable, DO storage pools might contain
many objects that are frequently reused. Loss of a DO storage pool
at this stage might significantly increase the time required for the
next complete system build, but not for subsequent builds, which can
reuse the newly created DOs.
- Mature projects might refer to DOs that are hard to rebuild (they
might require compilers that are no longer available, or views that
were deleted). These DOs are valuable, and should be backed up regularly
or, better yet, stored as elements in a VOB.
Even if you do not back up entire DO pools, back up at
least the pool root directory (d\ddft, for example)
and pool_id file. This practice prevents pool
root check failures from checkvob after the VOB
is restored.
Cleartext pool backup
Backing
up cleartext storage pools is not important, because type managers
re-create cleartext data containers as necessary.
Even if you
do not back up entire cleartext pools, back up at least the pool root
directory (c\cdft, for example) and pool_id file.
This practice prevents pool root check failures from checkvob after
the VOB is restored.
Administrative directory
backup
The admin directory contains
data about how much disk space that the VOB and its derived objects
use. The Rational® ClearCase® scheduler
runs periodic jobs that collect data on disk space use and store it
in this directory. By default, the scheduler stores data for the previous
30 days. This historical data cannot be re-created. If the data is
important, back up the admin directory.