[BackupPC-users] Backup start time and subsequent backups

[Vasan <vas...@gm...>]

Hi all,

We have scheduled backups for every day to be at 8:00PM in the evening
for one server host that has around 300GB in full to be backed up.
However, because of the innovative pooling mechanisms, it is clear
that the entire 300 GB is not getting backed up daily by backuppc as
per our expectations. We have scheduled full backups every alternate
day and incremental backup every day.

However, what we are observing is that backups are not being taken
every day... This is what is happening as per the status table

Backup 0        Start time: 8:00PM        Day 1
Backup 1        Start time: 8:03PM        Day 2
Backup 2        Start time: 8:01PM        Day 4

In between, it is supposed to take a full backup on Day 3 which it has
not taken. After going through the code base of Backuppc, we observe
that the first task that is done on first wakeup schedule is to do the
nightly jobs (pool compression, old backups deletion etc.). Since this
is time based backup configuration, the nightly job is done as the
first task on that time.

Depending on the amount of work that needs to be done, it looks like
that the time taken for the nightly jobs task to complete is varying
every day. In the case of Day 2, it has taken 3 minutes approximately
after which the backup would have started. Hence the backup start time
has been noted as 8:03PM.

For the next backup, it always seems to check for any modifications
during the last 24 hours. If for example, the next days nightly job
takes only a minute to complete (8:01PM), then first it will check if
any backup has been done for the last 24 hours at 8:01PM itself. In
this scenario, it will come out that the backup has been done in the
last 24 hours since the  last backup time was 8:03PM which is less
than 24 hours of the current time. Because of this, it skips this day
and goes on to the next day's backup.

This is turning out to be an serious issue as this results in a loss
of one day's backup completely. Please throw some light on the
veracity of our observations and advice on how this issue can be
resolved.

Thanks in advance for your help and inputs on this issue,

Srini