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Re: Wise disk parting.



On Wed, 2007-11-07 at 10:39 -0700, Steve Lindemann wrote:
> Mikkel L. Ellertson wrote:
> > Steve Lindemann wrote:
> >> In days gone by the rule of thumb for *nix was swap should be 1/2 the
> >> size of RAM.  Hadn't heard about that rule changing, but then I'm not on
> >> the bleeding edge these days....  though on my servers with 16GB of RAM
> >> it felt like a bit much setting swap to 8GB (but I did it anyway 8^)
> >>
> > I though the old rule was to for swap to be 2x RAM. This was because
> > a core dump would use 1x RAM size of swap. This is no longer the
> > case. Now days, if you are doing suspend to disk, you need slightly
> > more then the amount of RAM in swap space, plus what you need for
> > normal operation. If you are not going to suspend to disk, then the
> > swap space needed depends on the system. If you have enough RAM, you
> > do not need any swap space. For example, this system has 1M of RAM,
> > and it normally uses more then 5M of swap space. There are no simple
> > rules for swap size any more.
> > 
> > The thing to remember is that swap space is used for when you do not
> > have enough physical  memory. It is sometime used for keeping
> > program that are sleeping handy for reloading, but still freeing up
> > RAM for other uses. (A program may get swapped out when more RAM is
> > needed, and left swapped out even though there is RAM being used for
> > buffers...)
> > 
> > Mikkel
> > 
> hhhmmm.... now that you mention it, I do remember way *way* back using 
> 2x RAM for swap.  But we were lucky to a 1MB of RAM back then, 256K and 
> 512K was pretty common in the big servers.  Somewhere along the way, as 
> RAM size increased, I picked up the 1/2 RAM rule of thumb (probably when 
> we passed the 1MB mark) and it's worked ok for me for some while now so 
> I pretty much forgot about the 2x rule of thumb.   I wish I could blame 
> old age, but I've pretty much always had a rotten memory (probably could 
> use some swap space of my own  8^)
----
how to locate problematic memory banks...

linux memtest86

Craig


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