If you ever need to get some meaningful facts in a possible Redis vs memcached discussion you might want to benchmark both on your target system.

While Redis brings a tool redis-benchmark, memcached doesn't. But Redis author Salvatore Sanfilippo ported the Redis benchmark to memcached! So it is possible to measure quite similar metrics using the same math and result summaries for both key value stores.

Benchmarking Redis

So setup Redis in cluster mode, master/slave, whatever you like and run the Redis benchmark
apt-get install redis-tools	# available starting with Wheezy backports
redis-benchmark -h <host>

Benchmarking Memcached

And do the same for memcache by compiling the memcached port of the benchmark
apt-get install build-essentials libevent-dev
git clone
cd mc-benchmark.git
and running it with
./mc-benchmark -h <host>
The benchmark output has the same structure, with more output in the Redis version compared to the memcached variant as each command type is tested and the Redis protocol knows many more commands.

See also Redis - Cheat Sheet