SSL session cache lifetime vs session ticket lifetime

[Maxim Dounin]

Hello!

On Tue, Mar 18, 2014 at 03:42:33PM +0400, kyprizel wrote:

> What will be the best way to do it?

Probably a flag in ngx_slab_pool_t will be good enough.

> 
> 
> On Tue, Mar 18, 2014 at 3:33 PM, Maxim Dounin <mdounin at mdounin.ru> wrote:
> 
> > Hello!
> >
> > On Tue, Mar 18, 2014 at 03:26:10PM +0400, kyprizel wrote:
> >
> > > Hi,
> > > currently SSL session lifetime and SSL ticket lifetime are equal in
> > nginx.
> > >
> > > If we use session tickets with big enough lifetime (12hrs), we get a lot
> > of
> > > error log messages while allocating new sessions in shared memory:
> > >
> > > 2014/03/18 13:36:08 [crit] 18730#0: ngx_slab_alloc() failed: no memory in
> > > SSL session shared cache "SSL"
> > >
> > > We don't want to increase session cache size b/c working with it is a
> > > blocking operation and I believe it doesn't work good enought in our
> > > network scheme.
> >
> > Just a side note: I don't think that size matters from performance
> > point of view.  The only real downside is memory used.
> >
> > > As I can see - those messages are generated by ngx_slab_alloc_pages()
> > even
> > > if session was added to the cache after expiration of some old ones.
> > >
> > > So, what do you think if we add one more config parameter to split
> > session
> > > cache and session ticket lifetimes?
> >
> > May be better approach will be to just avoid such messages?
> >
> > --
> > Maxim Dounin
> > http://nginx.org/
> >
> > _______________________________________________
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> > nginx at nginx.org
> > http://mailman.nginx.org/mailman/listinfo/nginx
> >

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-- 
Maxim Dounin
http://nginx.org/