SSL performance optimization with cache

Maxim Dounin mdounin at
Fri Dec 14 10:56:16 UTC 2012


On Fri, Dec 14, 2012 at 01:45:34AM -0500, justin wrote:

> Browsing my nginx error log noticed the following logged A LOT:
> 2012/12/13 21:37:18 [crit] 7968#0: ngx_slab_alloc() failed: no memory in SSL
> session shared cache "SSL_CACHE"
> If the cache fills, does it flush older entries for new entries? Basically,
> how does the SSL cache work exactly?

If there is no memory available in a shared cache, oldest 
non-expired session will be dropped.  In most cases this will be 
enough to create new session, but I wouldn't rely on this as this 
is more an emergency mechanism than a normal behaviour.

Maxim Dounin

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