Re: Moving DB

No, don't extend it!  If you do that then you can't delete the old volumes.  The
value for maximum extension is the amount of space in the sum total of database
volumes that is not currently being used for the database.  That number must be
larger than the size of the database volume you want to delete.

In other words it is that extendable space that is added when you define a new
volume that is used when you delete an old one.

Lets say you've been growing your database over the years, each time adding a
500 MB volume and extending it, so that now you have 5 volumes for 2500 MB.
Your max extension is 0, yout database is 80% used.  You decide to ditch the 5
500 MB volumes in favour of two 2000 MB volumes.

You define the first volume and now your max extension is 2000.  You could
delete four of the five 500 MB volumes at this point, and ADSM would move 2000
MB from them to the new volume.  Or, you could add the second volume, so that
now you have a total available space of 6500, with a maximum extension of 4000.
You delete the five 500 MB volumes one at a time, leaving you with two volumes
each 2000 MB, a allocate space of 2500 MB (just like uyou started with), and a
max extension of 1500 MB.  Your DB utilization is still 80% (of 2500 MB = 2000
MB).  You then extend the DB 1500 MB.  Your utilization drops to 50%, your max
extension is 0 MB, your max reduction is approximately 2000 MB, depending on
fragmentation.

Cheers...
Bruce

"Purdon, James" wrote:

> I believe that I extended the database before deleting the old volumes.  If
> you don't extend it, and there isn't space, it won't let you delete the old
> volumes.
>
> Though come to think of it, I may have actually accomplished  some of my
> moves by creating a third mirror volume for each db volume and then deleting
> the originals after they had synced up.
>
> Jim
> > ----------
> > From:         Fred Johanson[SMTP:fred AT MIDWAY.UCHICAGO DOT EDU]
> > Reply To:     ADSM: Dist Stor Manager
> > Sent:         Friday, March 26, 1999 2:02 PM
> > To:   ADSM-L AT VM.MARIST DOT EDU
> > Subject:      Re: Moving DB
> >
> > Tom, Jim, Richard,
> >
> > Thanks.  I tried that once, but probably under V2R1, and it didn't work,
> > which is why I used the other way.  One more question.  After I define the
> > new DB files, do I EXTEND the DB, or just DEL DBV on each fragment I want
> > to get rid of?
> >
> >
> >
> >
> >
> > At 04:38 PM 3/25/99 -0500, you wrote:
> > >No, you don't have to do that - you can append the new space to the
> > database
> > >as separate volumes and then go back and delete the old space, assuming
> > >everything is on the same ADSM server.
> > >
> > >No need to dump and restore the db, and no need to take ADSM out of
> > >commission.
> > >
> > >Jim
> > >> ----------
> > >> From:         Fred Johanson[SMTP:fred AT MIDWAY.UCHICAGO DOT EDU]
> > >> Reply To:     ADSM: Dist Stor Manager
> > >> Sent:         Thursday, March 25, 1999 3:42 PM
> > >> To:   ADSM-L AT VM.MARIST DOT EDU
> > >> Subject:      Moving DB
> > >>
> > >> As ADSM has gone from a pilot project to a production system, the DB
> > has
> > >> expanded to 10 pieces spread over 4 volumes (and mirrored).  It's just
> > >> grown as expansion is need.  Now, we have installed a RAID-5 system on
> > the
> > >> server, and I want to move the DB to a single, coherent place on the
> > new
> > >> devices and allow for a year or more of growth as I do so.  As I
> > >> understand
> > >> the procedure from the manual, I have to
> > >>
> > >>                 1.      DSMSERV DUMPDB devc=tape  (defaulting to
> > scratch)
> > >>                 2.      DSMSERV FROMAT 1 newlogname 1 newdbname (both
> > >> already de
> > >> fined by
> > >> DSMFMT??)
> > >>                 3.      DSMSERV LOADDB devc=tape vol=scratch from 1
> > >>
> > >> My hardware is a RISC/6000 AIX4.2.1, ADSM 3.1.2.13, with a 3494 tape
> > >> library and 4 3590 drives.  I have a DEVCONFIG file already.
> > >>
> > >> However, at least one thing in the manual has me confused: that I must
> > use
> > >> a LIBTYPE of manual.  Does this mean I have to edit the DEVCONFIG (or
> > >> point
> > >> to another one) so that the LIBTYPE is manual?  If so, do I have to use
> > an
> > >> mtlib command to get a scratchtape mounted, rewound, and remounted?
> > Any
> > >> help will be greatly appreciated.
> > >>
> > >>
> > >>
> > >> Fred Johanson
> > >> System Administrator, ADSM
> > >> S.E.A.
> > >> University of Chicago
> > >> 773-702-8464
> > >>
> > >
> > Fred Johanson
> > System Administrator, ADSM
> > S.E.A.
> > University of Chicago
> > 773-702-8464
> >

--
Bruce Elrick, Ph.D.
Bruce Elrick, Ph.D.
mailto:belrick AT home DOT com
http://members.home.net/belrick/