[ubuntu-uk] Ubuntu Servers

[Chris Rowson]

On Wed, Dec 3, 2008 at 4:51 PM, Tony Travis <ajt at rri.sari.ac.uk> wrote:

> Chris Rowson wrote:
> > [...]
> > I've always used 32bit edition on servers myself. I've heard horror
> > stories about perl scripts using twice as much memory under 64bit etc,
> > etc.... I've never tested PAE with more than 4GB of RAM - I had heard
> > about the single process limitation, but as I only had 4GB to play with,
> > I've never had the opportunity to hit that limit!
>
> Hello, Chris.
>
> In fact you can only alloc() 2GB in a contiguous block if you have 4GB
> RAM installed. You can get somewhere near 3GB in total per process if
> you don't care about memory fragmentation with 4GB RAM installed.
>
> Things improve quite a lot with 8GB installed, but you still can't get
>  >4GB per process using PAE. For many programs that's not a problem, and
> you're right about 64-bit doubling the size of memory usage in certain
> situations. Actually, I don't think 64-bit is worth it unless you have
> very BIG memory problems to solve. PAE is quite good if you want to run
> multiple instances of programs that have < 4GB memory footprints.
>
> Bye,
>
>        Tony.
> --
> Dr. A.J.Travis, University of Aberdeen, Rowett Institute of Nutrition
> and Health, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
> tel +44(0)1224 712751, fax +44(0)1224 716687, http://www.rowett.ac.uk
> mailto:a.travis at abdn.ac.uk, http://bioinformatics.rri.sari.ac.uk/~ajt<http://bioinformatics.rri.sari.ac.uk/%7Eajt>
>

Thanks Tony,

As ever you helped expand my mind on the list :-)

Chris
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