Setting sysgen values

[Clayton_12]

Hi
I'm trying to modify some system parameters for SAS install.

How do I set minmum values for following sysgen parameters:
channelcnt
ctlpages
ctlimglim
procsectcnt
wsmax

Thanks
Clayton

[Heinz W Genhart]

Hi Clayton

You have to edit SYS$SYSTEM:MODPARAMS.DAT

There you enter lines like the following (or change the line if it exists allready)

min_channelcnt = x
min_ctlpages = y
min_ctlimglim = z
min_procsectcnt = t
min_wsmax = v

Then you have to execute autogen.

@sys$update:autogen savparams setparams check_feedback (as a example only)

After executing autogen, I recommend to review SYS$SYSTEM:AGEN$PARAMS.REPORT.

Additional I recomend to do a

$ Diff/par Sys$system:setparams.dat

You can then see in the differences output all changed systemparameters.
Finnaly you have to reboot your machine

I hope this answers your question

Regards

Heinz

[Duncan Morris]

In general use the construct MIN_paramname to set a minumum value for the parameter in your MODPARAMS.DAT file.

i.e.

MIN_PAGEDYN = 34000000
MIN_PIOPAGES = 775

For further info on using AUTOGEN to set your system parameters, refer to the HP OpenVMS System Manager's Manual, Volume 2.
This is available on the documentation site at http://h71000.www7.hp.com/doc/os82_index.html

[Clayton_12]

Trying out the sugestions.
But can't verify minimum values are being updated from the modparams.dat file.

Should the updated min values show up in sysgen?
Thx
Clayton

[Duncan Morris]

Hi Clayton, when you ran AUTOGEN it created a new copy of the parameter settings which will be used in subsequent boots.

You can manually change parameters which are "DYNAMIC", but most of yours are not dynamic - and will only be picked up on a reboot.

from SYSGEN type USE CURRENT to set the display to see the values that will be used in the next boot

USE ACTIVE will allow you to display the values that are in active use at that instant in time.

[Heinz W Genhart]

Hi Clyton

they will show up after a reboot or You have to do the following after executing autogen:

$ mc sysgen
SYSGEN> USE SYS$SYSROOT:[SYSEXE]ALPHAVMSSYS.PAR
SYSGEN> SHO 'your-changed-parameter-name'

This parameterfile (sys$sysroot:[sysexe]alphavmssys.par) will be loaded during next reboot

Regards

Heinz

[Wim Van den Wyngaert]

Be carefull.

It is possible that the node is not using the modparams system and that the previous manager has set all values by hand in sysgen. Compare before/after results of all parameters.

Wim

[Clayton_12]

I'm not sure still:-(

But after reboot my current values get set to the values I specified with the min parameters.
I guess default MIN values still shows up in the sysgen view.

Anyway as long as curent values are being set should be sufficient for my purposes.
If not I'll be back:-)

ONce again thnaks for all the feedback.
Input from ther community certainly complements the OPENVMS documentation well.

Clayton

[John Gillings · Accepted solution]

Clayton,

>I guess default MIN values still shows up in the sysgen view.

This is a very common, and easily understood misconception, leading from the rather odd SYSGEN interface. The columns labeled "Default", "Min", "Max", "Unit" and "Dynamic" are purely documentation. They are identical on all OpenVMS systems and cannot be changed.

"Default" is the value you get out of the box or from USE DEFAULT.
"Min" is the minimum allowed value
"Max" is the maximum allowed value
"Unit" is the unit of measurement (figure it out for TIMEPROMPTWAIT ;-)
"Dynamic" is a flag that tells you if the parameter can be changed on a running system.

Even the column labelled "Current" is a bit of a misnomer, as it's easily confused with the CURRENT parameter set. The column is the value in the parameter set you're looking at. On entering SYSGEN, the ACTIVE set is displayed - that is, what's active on the running system. "SYSGEN> USE CURRENT" will switch you to the boot values (which may be different from the active set).

Saying MIN_CHANNELCNT in MODPARAMS.DAT tells AUTOGEN that you want the value to be at least that value. AUTOGEN may choose a higher value. Running AUTOGEN to SETPARAMS will write the newly calculated parameter values to the CURRENT set to be used at next reboot. Anything which was changed should be reported in SYS$SYSTEM:AGEN$PARAMS.REPORT, or you can validate them with:

SYSGEN> USE CURRENT
SYSGEN> SHOW CHANNELCNT

compare with the ACTIVE value

SYSGEN> USE ACTIVE
SYSGEN> SHOW CHANNELCNT

Recommendation: If you're doing anything with SYSGEN, always issue an explicit USE command to ensure you really know which parameter set you're working with.

You can also create your own parameter sets with the WRITE command:

SYSGEN> USE CURRENT
SYSGEN> SET CHANNELCNT 4096
SYSGEN> WRITE MYPARAMS

Alternate sets can be invoked at boot time with a conversational boot:

SYSBOOT> USE MYPARAMS

Hopefully that clears up some of the confusion?

[Clayton_12]

Sounds good.
Thks for the explainantion.