Eric,

you are missing a big concept.  The server will never fail to select a
volume in a collocated pool even if there are no empty volumes, if there
are still volumes in filling status.
It will automatically start to double-up nodes by selecting the lest full
volume.  This is true for a existing node which has just
filled the volume it was initially assigned to and it is true for a new
node.

I have 1450+ nodes writting to 400 9840 tapes and have never had a volume
selection problem.  The server os 3.1.2.50 on os/390.


--
--------------------------
--------------------------
Bill Colwell
Bill Colwell
C. S. Draper Lab
Cambridge, Ma.
bcolwell AT draper DOT com
--------------------------
In <59C645F3B051D311A4680000832FE2D401AF12A5@X0F0000>, on 02/16/00
In <59C645F3B051D311A4680000832FE2D401AF12A5@X0F0000>, on 02/16/00
   at 11:25 AM, "Loon, E.J. van - SPLXM" <Eric-van.Loon AT KLM DOT NL> said:

>Hi Paul!
>You are right when you say that one should want to have his data spread
>over a minimum amount of tapes. However, I see a lot of clients that are
>using just one tape and only for a few percent.
>Because I'm using a rather "small" library (3575-L32) I cannot afford to
>give all new (small) clients their own private tape. I only have 320
>tapes in the library, so I'm limited to 320 clients (max.) when I'm using
>the collocated concept for all clients.
>Anyway, thanks for your answer! Guess I have to buy more disk so I can
>create a non-collocated diskpool.
>Kindest regards,
>Eric van Loon


>-----Original Message-----
>From: Paul Zarnowski [mailto:vkm AT CORNELLC.CIT.CORNELL DOT EDU]
>Sent: Tuesday, 15 February, 2000 23:31
>To: ADSM-L AT VM.MARIST DOT EDU
>Subject: Re: Collocation


>At 04:45 PM 2/15/2000 +0100, Loon, E.J. van - SPLXM wrote:
>>Hi *SM-ers!
>>I'm currently using collocation for all my nodes. I found out that a lot of
>>them are just using one tape and thus turning off collocation for them
>would
>>be wise.

>Eric;  It does not follow that turning off collocation would be wise if
>your nodes are using one tape each.  In fact, this is the desireable
>result of using collocation.  If you turn off collocation, you will find
>your node data spread across a bunch of tapes.

>>So I created a non-collocated primary tape pool for them and since I do not
>>want clients to backup directly to tape I also created a diskpool which has
>>the non collocated tapepool as next pool.
>>Now my problem: When I want to backup to this new diskpool I have to create
>>disk pool volumes for this diskpool, using the dsmfmt tool. I tried adding
>>the disk volumes I already use in the collocated diskpool to the
>>non-collocated diskpool, but that's not allowed by ADSM.
>>Does this mean that you cannot use the same physical disk volumes for both
>>collocated as non-collocated data? If that's the case, I will have to split
>>up my (already small) physical disk pool!

>This is correct.  One disk storage pool cannot be used to feed multiple
>sequential storage pools.  You need a separate disk pool for each
>sequential pool.

>>Am I overlooking something simple here?
>>Thanks in advance for any reply!
>>Kindest regards,
>>Eric van Loon

>..Paul