memcache memory limit

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memcache memory limit skyhopper 3/19/09 11:44 PM
Hi

is there a memory limit for the memcached process ? i want to run it
with -m 4096 option , is that possible ?
Re: memcache memory limit Dustin 3/20/09 12:01 AM

On Mar 19, 11:44 pm, skyhopper <sudipta.baner...@gmail.com> wrote:

> is there a memory limit for the memcached process ? i want to run it
> with -m 4096 option , is that possible ?

  What happens when you try?
Re: memcache memory limit Sudipta Banerjee 3/20/09 12:05 AM
actually ..i wanted to procure more ram. but someone just said that it doesn't allow more than 2 gig. thats why i wanted to confirm. right now i am on a 2 gig machine. but want to run memcached with 4 gigs of ram


thanks
Re: memcache memory limit Clint Webb 3/20/09 12:08 AM
Well if the machine had 4gb of ram, I wouldn't use 4096 for the -m option.  As I am sure that the OS and other bits are probably using some memory there.  I'd do 3800 or something, but depends on what else is being used on that server.--
"Be excellent to each other"
Re: memcache memory limit Sudipta Banerjee 3/20/09 12:10 AM
it has 8 gigs of ram and its 64 bit

its going to be dedicated to memcached

thanks
sudipta
Re: memcache memory limit Trond Norbye 3/20/09 12:36 AM

On Mar 20, 2009, at 8:10 AM, Sudipta Banerjee wrote:

> it has 8 gigs of ram and its 64 bit
>

Compile memcached as a 64bit binary and you should be able to use as  
much memory as you want (I have tested with up to 30Gb)... Please note  
that memcached use more memory than the memory specified with -m (for  
internal buffers etc), and you should leave memory for the os and  
other processes. The last thing you want is that your server is paging  
in and out memory pages..

Cheers,

Trond


Re: memcache memory limit JC 3/20/09 1:51 AM
By the way, has anyone already tried to quantify in a *more
scientific* manner the actual extra memory we should let on a box to
be sure memcached won't swap ?

I guess memcached related overhead should be proportional to the
expected number of connection and their traffic. I guess this is about
the same for the OS with its internal buffers. But I must confess that
so far, I don't know the exact multiplying factor(s) ...

Jean-Charles
Re: memcache memory limit Dormando 3/20/09 11:45 AM
It's at least "a couple megs". It depends on how many parallel connections
you have, and the typical size of your read buffers.

If you do a lot of large multi-gets, you'll use more ram than otherwise.
Future releases will probably track this memory more closely? It's not
hard to do.

-Dormando