Thanks to all that contributed to this thread. We recently separated two lines 
of business, each with its own sysplex, jesplex, etc.

As it turns out, I discovered the reason for the TGSIZE=24: tens of thousands 
of small PRT jobs generated daily.

So while I won't be changed that JESPLEX environment, I will be going with the 
default of 30 in the other JESPLEX environment.

Have a great day! Stay safe and healthy!!

Bob

-----Original Message-----
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of 
Mark Jacobs
Sent: Wednesday, April 22, 2020 7:35 AM
To: [email protected]
Subject: Re: JES2 SPOOLDEF TGSIZE recommendation sought

I was actually working on a local site problem that required reading up on this 
very topic a week or so ago. On a 3390 formatted track JES2 there are 12 
buffers(with BUFSIZE=3992). So your TGSIZE of 24 meant that JES2 would allocate 
2 tracks at a time. Changing TGSIZE to 30 will actually result in 36 buffers 
being allocated, using three tracks.

Mark Jacobs


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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Wednesday, April 22, 2020 7:27 AM, Jousma, David 
<[email protected]> wrote:

> Yea, just getting my coffee too... Looks like TGSIZE is easy enough to make 
> larger, no so much to make smaller....I guess if you are going to change, 
> then make the change before you add the new volumes. Once formatted, it 
> doesn't change?
>
> TGSIZE=nnn|30
> Specifies the number (1-255) of JES2 buffers to be contained in a track 
> group. JES2 uses this value to determine the number of tracks in a track 
> group on each spool device. This is the default value for the number of track 
> groups for each new spool volume added to the complex. Because the number of 
> tracks in a track group will vary based on the track capacity of the device, 
> the resultant value is rounded to the minimum integral number of tracks that 
> can contain the specified number of buffers.
> If you specify TGSIZE=, it must contain a value from 1 to 255. Regardless of 
> the value specified, the minimum resulting track group size is one track and 
> the maximum is the smaller of 255 and the number of tracks in the first 
> extent of the SYS1.HASPACE data set with the least number of tracks.
>
> Note: If you do not specify TGSIZE= as the same value on all members of the 
> complex, JES2 might not use the value specified here for a new spool volume.
> Performance Considerations: Attempt to tailor the value of TGSIZE to fit the 
> majority of the jobs in your system. SMF type 26 records can be used to 
> assist your choice of a value for this parameter.
>
> Small values for TGSIZE= can cause an excessive number of track group 
> allocations per job thus increasing processor overhead. For example, an 
> IEFBR14 job requires 13 spool buffers for control blocks and JCL data sets; 
> therefore, set the value of TGSIZE= greater than 13. Large values for TGSIZE= 
> can waste spool space and unnecessarily increase seek time.
>
> Modification: Minimum action to modify is $T SPOOLDEF to increase and a JES2 
> cold start to decrease.
>
> Dave Jousma
> AVP | Manager, Systems Engineering
>
> Fifth Third Bank  |  1830 East Paris Ave, SE  |  MD RSCB2H  |  Grand 
> Rapids, MI 49546
> 616.653.8429  |  fax: 616.653.2717
>
> -----Original Message-----
> From: IBM Mainframe Discussion List [email protected] On Behalf Of 
> Richards, Robert B.
> Sent: Wednesday, April 22, 2020 7:00 AM
> To: [email protected]
> Subject: Re: JES2 SPOOLDEF TGSIZE recommendation sought
>
> CAUTION EXTERNAL EMAIL
>
> DO NOT open attachments or click on links from unknown senders or 
> unexpected emails
>
> Dave,
>
> At your request! I should have provided it before...now where is that 2nd cup 
> of coffee?
>
> Bob
>
> SPOOLDEF BUFSIZE=3992,DSNAME=SYS1.HASPACE,DSNMASK=,
> FENCE=(ACTIVE=NO,VOLUMES=1),GCRATE=NORMAL,
> LASTSVAL=(2007.287,19:42:13),LARGEDS=ALLOWED,
> SPOOLNUM=64,TGSIZE=24,TGSPACE=(MAX=2443200,
> DEFINED=1900575,ACTIVE=1900575,
> PERCENT=32.1218,FREE=1290076,WARN=80),
> TRKCELL=3,VOLUME=JESS
>
> -----Original Message-----
> From: IBM Mainframe Discussion List [email protected] On Behalf 
> Of Jousma, David
> Sent: Wednesday, April 22, 2020 6:56 AM
> To: [email protected]
> Subject: Re: JES2 SPOOLDEF TGSIZE recommendation sought
>
> It would be helpful if you could post the output of a $DSPOOLDEF 
> command. We run with mod-54's with no issues. Just make sure you code 
> LARGEDS=ALLOWED
>
> $SPOOLDEF
> SPOOLDEF BUFSIZE=3992,DSNAME=SYS1.HASPACE,DSNMASK=,
> FENCE=(ACTIVE=NO,VOLUMES=1),GCRATE=NORMAL,
> LASTSVAL=(2007.294,12:08:34),LARGEDS=ALLOWED,
> SPOOLNUM=96,TGSIZE=30,TGSPACE=(MAX=2524640,
> DEFINED=1202032,ACTIVE=1202032,
> PERCENT=49.1162,FREE=611639,WARN=80),
> TRKCELL=3,VOLUME=JESD
>
> Dave Jousma
> AVP | Manager, Systems Engineering
>
> Fifth Third Bank  |  1830 East Paris Ave, SE  |  MD RSCB2H  |  Grand 
> Rapids, MI 49546
> 616.653.8429  |  fax: 616.653.2717
>
> -----Original Message-----
> From: IBM Mainframe Discussion List [email protected] On Behalf Of 
> Richards, Robert B.
>
> Sent: Wednesday, April 22, 2020 6:49 AM
> To: [email protected]
> Subject: JES2 SPOOLDEF TGSIZE recommendation sought
>
> CAUTION EXTERNAL EMAIL
>
> DO NOT open attachments or click on links from unknown senders or 
> unexpected emails
>
> For years, we have run with 3390-3 spool volumes and a TGSIZE=24. I am not 
> sure when or why the default became 30 and why it was not changed in my shop. 
> Probably the wisdom of it is not broke, do not fix it. Okay, so much for 
> history.
>
> Shortly, there will be a push to go to all higher capacity spool volumes. At 
> the moment, it looks like we are going to MOD-27s. What I am trying to 
> determine is a better value for TGSIZE given the migration to the MOD-27s. 
> TGSPACE has recently been tripled (still relatively small at 2.4 million). 
> The rest of the numbers associated with SPOOLDEF are defaults.
>
> Any suggestions would be appreciated. If it matters, DS8886 DASD.
>
> Thanks in advance!
>
> Bob
>
>
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