How do I increase free list size

[Paul cotton]

Could someone please tell me what i need to do in order to increase the free list size on an AlphaServer.

[Karl Rohwedder]

Paul,

just buy more memory... :-)

There are a lot of sysgen parameters around the freelist size and its treatment by VMS.

Unless you are a very experenced system administrator I would suggest to use the AUTOGEN facility to to the treaking.

After some days of 'normal' system load do a
$ @SYS$UPDATE:AUTOGEN SAVPARAMS TESTFILES
and review the SYS$SYSTEM:AGEN$PARAMS.REPORT.

If no errors or severe warnings were present, redo the run with
$ @SYS$UPDATE:AUTOGEN SAVPARAMS SETPARAMS
and perform a reboot at some convient time.

And read the manuals, as usual.

regards Kalle

[Jan van den Ende]

Paul,

The Free List size is a bit of a hidden presence these days!

If you have XFC activated (normal thing from V7 onward) then the available (otherwise unused) memory, upon release was formerly given to the free list, but nowadays any once-accessed disk file stays mapped in the XFC cache. (well, currently forgetting all gory details).
And this helps performance enormously, but hides the memory not currently in use.

Way out the best you can do, is follow Kalle's advise, and let AUTOGEN handle it.
Tweaking by MODPARAMS is possible, but DOES require understanding of the various memory influencing params.

The System Management Manual does provide a good overview, and does handle the relations between various params.

hth

Proost.

Have one on me.

jpe

[Paul cotton]

Paul,

just buy more memory... :-)

There are a lot of sysgen parameters around the freelist size and its treatment by VMS.

Unless you are a very experenced system administrator I would suggest to use the AUTOGEN facility to to the treaking.

After some days of 'normal' system load do a
$ @SYS$UPDATE:AUTOGEN SAVPARAMS TESTFILES
and review the SYS$SYSTEM:AGEN$PARAMS.REPORT.

If no errors or severe warnings were present, redo the run with
$ @SYS$UPDATE:AUTOGEN SAVPARAMS SETPARAMS
and perform a reboot at some convient time.

And read the manuals, as usual.


Karl

thanks for your response. I neglected to include quite a bit of detail on my original post. Basically the system in question is a DS25 at one of our sites on Malaysia, that I've recently been asked to manage - having previously been left completely unattended
(in terms of system/performance management) but still supporting live userbase.


The modparams.dat on this system was completely unpopulated until I looked at it this week. I increased the values of freelim, growlim & borrowlim (to all have the same value- 498) and increased freegoal to be 6 times this value and also applied changes to system yesterday using autogen.

The system was rebooted this morning but the free list size is still set at the original value of 512K (system has 4Gb of physical memory). Could this be due to the fact that autogen hasn't been run long enough to generate any meaningful feedback data and therefore changes I made won't filter through until autogen has been run for a few more days (and system rebooted again?)

[Volker Halle]

Paul,

please explain, what problem you are seeing or what you are trying to achieve.

Volker.

[Wim Van den Wyngaert]

It's been a long time but
@SYS$UPDATE:AUTOGEN SAVPARAMS SETPARAMS
aborts when there are errors. And thus the setparams is not done.
You need to do @SYS$UPDATE:AUTOGEN SETPARAMS
by hand again.

Fwiw

Wim

[Paul cotton]

Paul,

please explain, what problem you are seeing or what you are trying to achieve.

Volker


Well the issue that is being reported to me is that the system is hanging with 50 users connected. I then noticed that free list becomes exhausted at about the same time
as users report the system hang.

[Paul cotton]

It's been a long time but
@SYS$UPDATE:AUTOGEN SAVPARAMS SETPARAMS
aborts when there are errors. And thus the setparams is not done.
You need to do @SYS$UPDATE:AUTOGEN SETPARAMS
by hand again.

Fwiw

Wim


Wim,

The autogen changes I made yesterday did get applied to the system but have not resulted in the free page size increasing.


regards
paul

[Wim Van den Wyngaert]

This gives some info about the interaction of xfc and the free list.
http://unix.derkeiler.com/Newsgroups/comp.os.vms/2004-09/2224.html

Wim

[Hein van den Heuvel]

A picture speaks a thousand words, even if it is a picture of words....

Please attach a .TXT file with the output for $SHOW MEM/FULL when the system was nicely used, SYSGEN SHOW /MAJOR and toss in a SHOW SYSTEM or MONI SYSTEM (per process memory) output while collecting.

It is quiet possible there simply is not enough physical memory.

And focus on history.
You suggest is worked fine unattended. Well, stop attending!

What else changed? More users?

Were the working set params tweaked such that now memory is overcommited?
Was a dababase cache tweaked, making it use more memory?

Hope this helps some,
Hein van den Heuvel (at gmail dot com)
HvdH Performance Consulting