Memory Ceiling

Brett Richter brett at
Wed Aug 9 19:36:00 UTC 2006

giving the Pre2 a try.. let you guys know what happens!
On Aug 9, 2006, at 3:07 PM, Steven Grimm wrote:

> Ah, yes, excellent point! If you're graphing the total size of  
> items in the cache, rather than the process memory usage, then  
> 700MB is about right for 1.1.12. Grab 1.1.13pre2 or search this  
> list for my memory efficiency patches to 1.1.12 if you want to  
> increase that; with my patches the efficiency is more like 85-90%.
> When you're at 700MB, what does "top" show for the total process size?
> -Steve
> Matthew Nielsen wrote:
>> 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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