Web Service Tier
Web server which can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache for Koha ILS. The Web Service Tier is a high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server. The Web Service Tier is known for its high performance, stability, rich feature set, simple configuration, and low resource consumption.
Application Tier
The application tier, which may also be referred to as the logic tier, the Koha ILS engines the application’ core functions. This application tier can either be hosted on distributed servers in the cloud or an a dedicated in-house server, depending on the requirement of the library, such as how many concurrent users and what is the response time, to identify the processing power for the application.
Data Tier
The data tier consists the Koha ILS database. This tier may also be referred to as the stronger tier and can be hosted on-premises or in the cloud. Koha ILS is adopting MySQL or Maria DB. Please refer also Edge Tech DB Policy for strong/async/sync the data from the main database to another backup server to achieve 0 data loss.