Memory Ceiling

Matthew Nielsen xunker at
Wed Aug 9 19:01:24 UTC 2006

I don't know how cacti shows its graphic on this (amount used by the  
total process versus the memory used by the items in the cache), but  
it's worth noting that memcache is only about 70% efficient at the  
moment so getting 700MB of usable cache out of -m 1024 is inline with  
what we'd expect.

-Matthew Nielsen

On Aug 9, 2006, at 12:54 PM, Brett Richter wrote:

> thanks for the quick reply... the line def says -m 1024 but it  
> never goes higher than 700mb (we use cacti graphs).  And yes those  
> werid debian guys! it uses a conf file..
> Any other suggestions?
> On Aug 9, 2006, at 2:48 PM, Steven Grimm wrote:
>> Memcached doesn't have a config file per se (must be something the  
>> Debian guys added) so the first thing to look at is what command  
>> line parameters are getting passed to the actual memcached  
>> process. The one you want to look at is "-m", which controls the  
>> cache size. If you run "memcached -m 1024" then the cache should  
>> grow up to 1GB.
>> As for using all three of your servers, that is most likely a  
>> client configuration issue. The client is responsible for choosing  
>> which server to use for a particular key; if the client is only  
>> configured to know about one of the servers, it will never contact  
>> the other two.
>> -Steve
>> Brett Richter wrote:
>>> I'm sure this has been asked a million times but we seem to be  
>>> running up against a memory ceiling on memcached.  We use it to  
>>> cache dynamic content of our website.  No matter how high I set  
>>> the memory limit in the conf file it never goes higher than 700mb  
>>> (give or take).  We definitely need more than that as any hit  
>>> that doesn't hit the cache is going to the database and its  
>>> getting overwhelmed at times.
>>> A bit about our setup. We have 3 servers running memcached, both  
>>> set to 1024mb memory.  It seems that it's really only using 1  
>>> server right now (looking into why its not using the pool of 3),  
>>> so I really need to get one up to like 3gb till we can look at  
>>> the code and see why its not using the memcache pool better (or  
>>> at all).
>>> Systems are Debian Stable 64 using one of their packaged  
>>> memcached installs version 1.1.12-1 of memcache
>>> Sorry if this seems cryptic of not enough detail I'm the sysadmin  
>>> not the developer of the back end content manager.
>>> Any help would be great!
>>> Thanks!

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