[ale] that same darn NFS problem SOLVED

[Jeffrey B. Layton]

Calvin Harrigan wrote:

> At 02:38 PM 2/17/2003 -0500, Michael D. Hirsch wrote:
>
>> On Monday 17 February 2003 02:30 pm, Chris Ricker wrote:
>> > On Mon, 17 Feb 2003, James P. Kinney III wrote:
>> > > With a 2.4.x kernel and RAM <=4G swap=2xRAM
>> >
>> > That's not necessary. There was a bug in early 2.4.x that required
>> > swap=2xRAM for decent performance, but that's long since been fixed...
>> >
>> > You need enough swap to hold your working set. That could be anything
>> > from no swap to gigabytes, depending on what you do on that system....
>
>
> <snip>
>
> The 2xRam argument is understandable, but questionable/confusing (at 
> least in my opinion).  I have 128Megs Ram, a 256MB swap, fine.  I'm 
> swapping too much, I add another 256Megs of Ram, according to the 
> argument I should now increase my swap to 768MB (384MB ram total).  Why?
> Isn't the whole point of adding more memory to get away from swapping?
> Just a question I've asked several times without a good answer.


   From what I've been told, the rule of thumb is 2x
physical memory for swap space. I also have never
heard a good reason, except in the case of HPUX
which allocates swap space equal to the memory
allocated for an application (so that if it swaps out
completly there will be swap space available for
it). On the other hand you can tune this feature in
HPUX.
   My only comment about increasing the amount of
swap when the RAM increases is that one might
run an application that uses more physical memory
and if it swaps is likely to need more swap space.
However, this comment may or may not apply to
you or anyone. Also, if you can repartition your HD,
then you can easily add another swap partition (and
if you put it on another drive and set things up
carefully, you can stripe your swap space across the
drives! But then again, if my app starts swapping
I want to find out why and stop it).
   Personally, on my servers and desktops, I put 2x
the RAM as swap space, just in case I need it. Then
I monitor swap usage closely (particularly on the
servers). If I see swapping, I look at the box to find
out what's going on (what apps are running, who's
logged in, etc.). I don't like swapping apps :) Then
if I discover there's a need for more memory, we
go get it (we can use it as justification for getting
more memory).
   Again, these are things I do. I have never found
any hard and fast rules (except for HPUX, but you
can tune those settings).

Good Luck!

Jeff

>
>
>
> Calvin...
>
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://www.ale.org/mailman/listinfo/ale
>



_______________________________________________
Ale mailing list
Ale at ale.org
http://www.ale.org/mailman/listinfo/ale