How to determine a memcached server is OVERLOAD?

[dormando]

> i'm wondering is there a way(or standard) to measure that memcached 
> server in OVERLOAD or not?
> 
> if it's in OVERLOAD status. what can i do ? just add more memcached 
> servers and add more RAM usage?
> 
> any tips are appreciated. thank you all!!!

You should upgrade to 1.2.5. The version you are running (1.2.0) doesn't 
support eviction tracking.

You need to monitor a few things:

'evictions' - which will happen if all of your items do not have an 
expire time, _or_ you are storing too many new items and they don't get 
expired fast enough.
- The actual CPU usage on the box. If it's pegged, you're dead.
- If you're swapping. Just disable swap or something...
- If something else on the box is contending for cpu.
- If your network/switch/uplinks are pegged.

Otherwise memcached will happily chew up all of your box's resources.

-Dormando