Memcached and maximum persistent connections
dormando at rydia.net
Sat Oct 6 22:41:11 UTC 2007
64-per is a lot :)
Anyway, it's fine, go nuts. There's a comment next to the maxfiles section:
/* to limit connections-related memory to about 5MB */
... I have no idea how they arrived at this conclusion but it's not hard
to figure out. The only things to keep in mind:
- There are small memory allocations per connection.
- They're not presently tracked by the global memory limit, so memcached
will grow beyond that limit a wee bit based on your connections (and I'm
not man enough to fix it instead of just repeating this).
Robin Schuil wrote:
> Hi all,
> I'm trying to run memcached but had some trouble with the connection
> limit. Already found that I need to use the '-c <num>' option to
> increase the # of maximum simultaneous connections. However, I have 200
> webservers each with ~64 apache childs running (there may be peaks). If
> each process would create a persistent connection that would mean that
> each of my 10 memcached nodes have to handle 12,800 simultaneous
> I guess that shouldn't be a problem, but the low default maximum of 1024
> somewhat bothers me. Is it sane to start memcached with a limit of 40K
> connections, or is it likely that I'll run into other problems then?
> Your input is greatly appreciated.
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