how to calculate the label 0 backup file size

It will depend also on the activity on your system;

if a backup of a dbspace is running, then before images of pages will
be stored into temp space (which are needed to have
a complete backup) they will be appended to the backup media when the
backup of the dbspace completes.
Also the info in your trx log is needed. This may be big if a
transaction was started long before the backup began...


If there is no activity when the backup runs then you can look at the
npused in sysptnhdr which i think will give you a good
number.
you may have to run a select count(*) from sysextents before you query
syspnthdr (to get things in the cache..) or look at sysextents as
well.
Disadvantage is that the unused pages in tables are in there as well.

Superboer.




On 16 okt, 08:57, joe wrote:
> How can I know the backup file size after running 'ontape -s -L 0' .
>
> Can it tell  from  output of 'onstat -d'.
>
> Or select some information from sysmaster .