how small can I make the thread stack size?

Cosimo Streppone cosimo at
Wed Jul 28 10:29:42 CEST 2010

On Wed, 28 Jul 2010 08:02:50 +0200, Chris Hecker <checker at> wrote:

> [stack size] I've seen people talking about 256kb, but then the docs are  
> pretty sketchy on whether it's a good idea to change it at all,  
> Any advice?

We're running several varnish instances.
All of them x86-64 though, so YMMV.

For the busiest machines, stack size has been set to 256kb, by putting
'ulimit -s 256' in the init script.

IIRC, we started doing this because we saw increases in the  
We saw that varnishd couldn't create new threads,
even if the hard limit (thread_pool_max) hadn't been reached yet.

These particular instances are constantly running 7k threads,
occasionally going to 8-9k. With 24 Gb of RAM.


More information about the varnish-misc mailing list