What is Memcached?
"Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load" (https://memcached.org/).
Why we should use Memcached with Koha?
Memcached can boost the performance of Koha.
I have tried to enable Memcached with Koha versions 17.05.x to 18.05.x.
Check Memcached working with Koha
Open Koha > About Koha > Server Information
|The red flag indicates that Memcached not working|