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Table of Contents

For customers with a valid subscription we can offer a more extensive tuning and optimisation document. Please request it from our support portal.


Measuring Kopano performance

Kopano Stats

Kopano Stats is a command line tool to show various statistics about the health and performance of your Kopano Core installation. It can show several types of statistic tables (system metrics, active sessions, users and user-settings, companies, as well as a live "top"-like overview of the Kopano Core server. Calling Kopano Stats can be done with the following example command;

Code Block
$ kopano-stats --top

And will give you various metrics. The most important ones are explained below;

Round Trip Time

Round Trip Time (RTT) is the most important indicator for your performance, as it measures the time it takes to complete a request. A live calculation of the RTT will be shown with kopano-stats --top, which will fluctuate according to server load.


Anything below 40ms is normal and very acceptable speed, but values above 50ms can give the user some delay in user experience.

Threads (active and idle)

What can also be seen is the amount of Kopano Core server threads, pre-configured in the server.cfg and idle. A server thread is the smallest set of instructions that can be managed independently. Because of multi-threading, this amount can be preconfigured to the amount of CPU cores times 4, of which a certain amount will remain idle at low load.They remain in an idle state with allocated memory, ready to be used by the Kopano Core server when needed.


Low idle threads (1 or 2) in combination with high RTT's can indicates slow performance due to thread locking.

In even higher input load situations, more threads (than the pre-configured amount) will be created because of a higher number of (queued) requests, which can also be a good indicator of an incident

CPU load

The CPU graph in kopano-stats shows the general overview CPU usage only by the kopano-server. It is not uncommon to see spikes in peak times, continuous spikes can indicate resource issues.

Sessions and users

Queue length and age

Kopano Core server threads

The number of kopano-server threads. this amount can be preconfigured to the amount of CPU cores times 4

Kopano Core server caches

For performace reasons, it is strongly recommended to set the cache settings of the Kopano Core server appropriate for your setup/server. Each time a request on an item can be found in the cache (cache hits), this avoids calls to other processes and disks/storage. Setting sensible cache settings certainly increases the performance.


This cache contains unique id's of objects.

Cache statistics

To get the cache statistics from the Kopano Core-server process, you can send the USR1 signal to the server process.

kopano-stats --system