Tom wrote :

> I just added a new disc drive and added it to the system volume set and
> all went well.  What I'm curious about is the percentages for max
> transient and max permanent space using altervol in volutil.

OK, I'll try to be specific and answer on a question-by-question basis.

> The new drive ended up defaulting to 95% and 95% (the manual says the
> dafault is 100% and 100%)

AFAIK, default is 75%-75% for ldev 1 and 100%-100% for user volumes. No
idea what it is for non-ldev 1 system volumes. Perhaps 95%-95%.

> ... the manual says that LDEV 1 defaults at 75% and 75%.

True.

>  Why can this even be set?

Space usage on ldev 1 goes up and down, on both permanent (spoolfiles,
among others) and transient (virtual memory) counts. That's why default
limits add up to more than 100 %. This is usually not an issue.

>  What use is it?  Why do I need to give up 25% of the usable space on
LDEV 1?

You don't literally "give up" 25 % of ldev 1 space, you allow transient
space (i.e. virtual memory) to take up to 25% of ldev 1 space. Transient
space usage goes up and down with system activity, database usage, sessions
logging on and off, and so forth.

Unlike MPE V/E or HP-UX, MPE/iX does not require virtual memory to use a
pre-configured, fixed-size disc area. Instead, it copies unused portions
from main memory to "transient space" into "holes" (unused space) on system
volumes.

There is no transient space on user volume sets, hence the 100 % permanent
space default.

Another requirement is to make sure that MPE always can boot, whatever the
space usage on ldev 1. That's why volutil will NEVER allow you to configure
100 % permanent space on ldev 1. The maximum will always be 100 % minus 360
kilosectors (rounded).

>Does is end up taking 25% away from permanent space that can be used by
transient space?

That's a very simple view, but a rather true one.

> Why did the new drive end up at 95% 95%?

No 100 % sure idea. I would think you configured a volume other than ldev 1
into the system domain. Did you entre values for permament/transient limits
when you added your new volume in volutil ?

> What is the strategy involved here? The documentation is pretty bare
bones.

I once wrote a paper on disk space usage on MPE/iX. Sorry, it's in French.
If you understand French, I'd be glad to fax it to you.

HTH...

Christian Lheureux
Head of Systems and Networks Department
APPIC R.H.
An HPConnect Systems Integrator
An HP3000 Expert