Hi
I don't know if online backups have changed much since the distant days of 9.1 but I noticed something today that I've never realised happens and wondered if someone smarter than me can explain what is happening...
I run an online backup of a single DB to the same backup file name every day. The backup file isn't deleted before taking the backup. I've noticed that this backup file will remain at its peak size regardless of whether the DB decreases in data content. E.G. Day1 DB has 100MB of contents so backup is 100MB then Day2 DB decreases to 50MB but the online backup file remains at 100MB.
In the above example, if I delete the backup file before performing the backup then it is 50MB.
What's going on here?
Thanks in advance,
Grant
bug.
No, please! Don't treat it as a bug. It's a useful feature. Probkup (online and offline) writes to a beginning of an exitent file. That is why we can use the named pipes as a target.
Ok, thanks, so is this a known bug in 9.1?
If so, should I be explicitly deleting the old backup file before I run probkup then ?
> so is this a known bug in 9.1?
Probkup works the same way at least since V5 (1988).
> If so, should I be explicitly deleting the old backup file before I run probkup then ?
Yes, and you also should change some probkup's parameters like the -bf (blocking factor).
> On Oct 26, 2016, at 10:26 AM, George Potemkin wrote:
>
> No, please! Don't treat it as a bug. It's a useful feature. Probkup (online and offline) writes to a beginning of an exitent file. That is why we can use the named pipes as a target.
The backup program can tell the difference between a file on disk and a named pipe or mag tape, etc. so you don’t have to lose this feature. all that is needed is for the backup to truncate (not delete) the output disk file before it starts writing to it.