RAM question for everyone!

[Gilboa Davara]

On Fri, 2009-01-23 at 16:46 +0000, Bryn M. Reeves wrote:
> Gilboa Davara wrote:
> > Yeah, but this problem can more-or-less be avoided by
> > lowering /proc/sys/vm/swappiness.
> 
> Sure, that will make the VM more likely to evict pagecache data than 
> anonymous pages when it's trying to free pages.
> 
> I haven't tested this to any real degree on my desktop boxes (as I 
> don't really suffer too much from this with the setups that I run), 
> does it give a significant benefit for this case?
> 
> I can imagine it would given that systems where I have seen problems 
> like this have tended to seem a bit cache-heavy, but testing results 
> are always good to hear.
> 
> Regards,
> Bryn.
> 

To be honest, now-days, I rarely tweak the swappiness value. While it
was required on a 32bit machine with >2GB of memory, the default value
works just fine on most 64bit workstation (and server) I use these-days.
Even on servers with relatively long up times (>4 months), I rarely see
more than 100-200MB of swap being used. *

- Gilboa 
* Unless something goes horribly wrong (mostly due to admin error), in
which case, I'm glad that I had a lot of swap space ready "just in
case"...