[Systems] Memcached

Ivan Krstić krstic at solarsail.hcs.harvard.edu
Sat Mar 28 12:36:10 EDT 2009

On Mar 28, 2009, at 4:51 PM, David Farning wrote:
> (among other things) is still growing pretty quickly.

I'm not sure what you're trying to say. Memcached is a slab-allocated  
cache with a LRU ejection policy which is triggered only when the slab  
class selected for a new allocation is full. Optional expiration times  
for stored items are not taken into account by any kind of real-time  
garbage collector; they're just given precedence in the LRU calculation.

In other words, by definition, memcached memory utilization will keep  
growing until it hits whatever limit you gave it. This isn't bad. It's  
exactly how it's supposed to be, which is why the graphs you have are  
practically useless. You care about the cache utilization rate, not  
bytes used.

Ivan Krstić <krstic at solarsail.hcs.harvard.edu> | http://radian.org

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