[comp.sys.dec] Ultrix 4.1 on a VaxStation II/RC: losing memory with time??

jdubb@bucsf.bu.edu (jay dubb) (04/13/91)

   I am posting this for a friend of mine who doesn't have access
to USENET, so please respond directly to mlevin@jade.tufts.edu.

   Aabout a month ago I started up my VaxStation with Ultrix 4.1, and
the workstation software. It has 8 Megs of additional RAM, and
DecWrite, DecChart, and DecEquation. Its worked beautifully for the
month, with tons of processes going at once (kermit, DecTerm,
DecWrite, DecChart, switching between the windows) - nothing crashed,
and it worked just fine. But then I started getting messages that said
"out of memory - saving everything" from DecWrite. And now, several
things that I used to do before with no problem crash the program
completely, due to running out of memory. 
     Does anyone know what is going on? Where oh where has my memory
gone? I have heard of "growing X servers", but maybe this has nothing
to do with it (I know next to nothing about windows stuff).  I note
that my X server, Xqvsm, is about 1 meg large, and there is also
a Xqvsm.new (where did this come from??) also about one Meg large. Is
this normal? Please help! 
	
					Mike Levin (mlevin@jade.tufts.edu)

mogul@pa.dec.com (Jeffrey Mogul) (04/18/91)

In article <78850@bu.edu.bu.edu> jdubb@bucsf.bu.edu (jay dubb) writes:
>   Aabout a month ago I started up my VaxStation with Ultrix 4.1, and
>the workstation software. It has 8 Megs of additional RAM, and
>DecWrite, DecChart, and DecEquation. Its worked beautifully for the
>month, with tons of processes going at once (kermit, DecTerm,
>DecWrite, DecChart, switching between the windows) - nothing crashed,
>and it worked just fine. But then I started getting messages that said
>"out of memory - saving everything" from DecWrite. And now, several
>things that I used to do before with no problem crash the program
>completely, due to running out of memory. 
>     Does anyone know what is going on? Where oh where has my memory
>gone? I have heard of "growing X servers", but maybe this has nothing
>to do with it (I know next to nothing about windows stuff).  I note
>that my X server, Xqvsm, is about 1 meg large, and there is also
>a Xqvsm.new (where did this come from??) also about one Meg large. Is
>this normal? Please help! 
>	
>					Mike Levin (mlevin@jade.tufts.edu)

Ultrix is a virtual-memory system, so "out of memory" really means
"out of swap space", not "out of 8Mb of RAM".  How can the system
be out of VM?  Perhaps your tons of processes going at once have
virtual memory requirements that add up to more than can be fit
into your swap space.  Also, almost all space allocation schemes
can suffer from "fragmentation" over time, and the Ultrix swap space
algorithm is no different.  So, your total swap space requirements
may be less than the size of your swap area, but over time the swap
space may become so fragmented as to waste a sizeable amount of space.

"/etc/pstat -s" will give you some information (fairly cryptic) on
the state of your swap space.

You might need to use more swap space, or few processes at once, or
reboot once in a while to clean the gunk out.

-Jeff