RE: RCLSTG (Was: Preventative Maintenance For AS400)

It's an unfortunate name, Reclaim Storage has little to to with wasted
disk space.

From:
http://www-912.ibm.com/s_dir/slkbase.nsf/90402cf55bdbcdc786256ffd0076ec0
5/9373303619fb4b89862565c2007d4bcf?OpenDocument&Highlight=0,rclstg,overv
iew

RCLSTG does the following:

        *       RCLSTG addresses each object and then validates the
headers and pointers for that object.
        *       Finds orphaned objects.
        *       Function checks when hard damage is encountered.
        *       Corrects, where possible, objects that were incompletely
updated (such as database files, libraries, device descriptions,
directories and stream files) and user profiles containing incorrectly
recorded object ownership information.
        *       Deletes any unusable objects or fragments. 

For the most part I would say that the iSeries cleans up it's messes as
well as any system can (Rob's Management Central case notwithstanding.)
Most damaged objects are automagically recreated by the system during
IPLs.  I would guess that the majority of RCLSTG's are run to clean up
after power failures.

In our particular case, I think that the length of time for the RCLSTG
was probably due to the large number (7 million plus) of small objects
and the fact that these objects were in a UDFS on external DASD.  Our
previous RCLSTG ( two years ago) only took two hours and I found no
evidence of extensive object damage in this one, it just ran forever.
Now that I think about it, at that time we still had about 1 million
DLOs.

Regards,
 
Scott Ingvaldson
iSeries System Administrator
GuideOne Insurance Group


-----Original Message-----
date: Thu, 25 Aug 2005 14:51:45 -0600 (MDT)
from: James Rich <james@xxxxxxxxxxx>
subject: Re: RCLSTG  (Was: Preventative Maintenance For AS400)

What exactly is being reclaimed by RCLSTG?  The name "reclaim storage" 
implies that there is wasted disk space out there.  Why is space being 
wasted?  Is there any reason why OS/400 can't take care of this wasted 
space automatically?  Why is it wasted in the first place?

As far as damaged objects, what is damaged about them?  Why are they
being 
damaged?  Shouldn't this damage be prevented?

RCLSTG seems like a "clean up the messes" type program.  Why are the 
"messes" being created in the first place?  Make sense?

James Rich