In our Zammad instance with around 12-16 active agents and ~12k tickets I implemented 4 tuning enhancements that really helped boost the performance:
- set WEB_CONCURRENCY to 4
- move the tmp dir to a ramdisk
- move attachments from the database to the filesystem
- limit the number of tickets that are enumerated in overviews. Example: I renamed closed tickets to “Recently closed tickets” and limited it to the last 3 months or so. Having many overviews showing lots of tickets slows down your system so limit overviews as much as possible
After that we never had performance issues again.