Jerry Lawson asked:

>At any rate, you mentioned logmode=rollforward.  We have been considering
>this, but as I was reading, all I saw wa the comment about how it would use
>more space that the "normal" recovery method.  Now I know IBM will roll out
>their favorite answer number 2 ("It Depends"), but would like to have some
>sort of an idea what to expect.  How much of an increase did you see?  What is
>your normal daily activity?
>
>Has anyone else used Rollforward, and if so, how much increase did you see.

I've used the recovery log in roll-forward mode. I found that my recovery log
needs increased from 100 MB to around 500 MB (although I allocated 900 MB just
to be safe, and for future growth) when I implemented roll-forward mode. This
was for a 1.9 GB database. The activity came from backing up around 11 - 13 GB
per night (max), daily inventory expiration, storage pool backup, migration,
and reclamation (the big hitters). I was also incrementally backing up my
database on a daily basis.

Once you're on version 2, you can try to get a good idea yourself of how much
additional space you'll need.

Let's assume that you will back up your database daily. Once a day (at the same
time every day - the "logical" end of your daily ADSM activity might be a good
time) issue the following admin commands:

   QUERY LOG FORMAT=DETAILED
   RESET LOGCONSUMPTION

The output from the QUERY LOG command includes a line item called 'Cumulative
Consumption (MB)'. This shows you, in MB, the amount of change that occurred
in your database since the last time you issued RESET LOGCONSUMPTION. By doing
this every day for a week or so (or whatever time period you are comfortable
with - make sure the numbers are fairly consistent) you can get an idea of
how much additional recovery log space you'll require. Although I found the
statistic to be pretty much "on the money", I'd still add a little extra just
to be on the safe side. So yes, as you indicated earlier, the answer really is
"it depends".

Andy Raibeck
ADSM Level 2