first time user with out of memory question

Perrin Harkins perrin at elem.com
Mon Jun 12 14:54:28 UTC 2006


Mauro Nicolas Infantino wrote:
> Even with enough memory, and a memcached server only working for the 
> session management, there's still a chance that some session data get 
> lost?

Of course.  What if you get a surprise flood of traffic that fills up 
the cache, maybe from a bot?  What if memcached hits an obscure bug in 
some library and the daemon crashes?  What if your memcached server has 
a hardware failure of some kind?  All of your session data will be lost. 
  Unlike a database, there's no replication in memcached so you can't 
failover with your data intact, and no disk storage that would save it 
if the daemon just went down for some reason.

> I mean, maybe memcached was not designed to store sessions, but if under 
> the right conditions it works ok, it could be a nice solution.

If "the right conditions" means "it's okay to run a slight risk of 
losing all our session data" then go ahead.  Don't kid yourself that it 
can't happen though.

- Perrin


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