Newbie question

[Peter van Dijk]

On Wed, Dec 07, 2005 at 10:49:08PM -0800, Jeff Rodenburg wrote:
> I'm new to memcached and need a little guidance.  I've got a relative
> understanding of how memcached works and would like to monitor the service.
> Is it possible to measure the available capacity of a running memcached
> instance?  For example, considering a memcached daemon allocated 2GB of RAM,
> how much available space exists on that instance?
> 
> My goal is to understand how much cache is being used in order to plan how
> many more daemons/systems we need to allocate.  I'm not even sure if this is
> an appropriate approach, but I wasn't able to find an answer in the mailing
> list archives.

# telnet localhost 11211
Trying 127.0.0.1...
Connected to localhost
Escape character is '^]'.
stats
STAT pid 7160
STAT uptime 12259115
STAT time 1134120329
STAT version 1.1.11
STAT rusage_user 152:349128
STAT rusage_system 284:196501
STAT curr_items 26837
STAT total_items 342093
STAT bytes 1594665
STAT curr_connections 1
STAT total_connections 814007
STAT connection_structures 7
STAT cmd_get 846178
STAT cmd_set 342078
STAT get_hits 764174
STAT get_misses 82004
STAT bytes_read 94808973
STAT bytes_written 182472401
STAT limit_maxbytes 134217728
END

Specifically, `bytes' is the amount of memory in use within memcache,
out of a maximum of limit_maxbytes (which would be ~2GB in your case).
However, keep in mind that `bytes' may count data that is ready to 
be expired but hasn't been removed yet.

Most client libraries have functionality to extract these statistics.

Regards,
Peter.