Q: How can I be sure the caching service is working as intended?

Reading the service log would be one way.

If you want more details, you can add client identity to the log file with this command:

sudo serveradmin settings caching:LogClientIdentity = true

Or you can

sudo serveradmin fullstatus caching

You can track stats there.

Reid

Apple Consultants Network

Author "El Capitan Server – Foundation Services" :: Exclusively available in Apple's iBooks Store

Author Mavericks Server and Yosemite Server series, also available in Apple's iBooks Store

I think the Debug.log is the most useful information you can have for the Caching Services:

tail -f /Library/Server/Caching/Logs/Debug.log

For me that log was written out of the box, but you might need to increase LogLevel according to

https://help.apple.com/serverapp/mac/5.0/index.html?localePath=en.lproj#/apd5E1A D52E-012B-4A41-8F21-8E9EDA56583A

in order for it to work.

Server app > Logs > Caching Service Log

Server app > Stats > Caching Bytes Served