In Preferences -> Interface -> General you find various Message Buffer settings for Smuxi. This settings tell Smuxi where to store received messages you see in every chat. Each continuous text line in Smuxi is a single message (line wrapping has no influence).
This setting tells Smuxi's frontend how many messages a single chat should retain before the oldest messages get removed once it exceeds that value.
By default Smuxi shows up to 500 messages per chat before it removes them. If you increase this value, keep in mind that it will increase the memory usage!
This setting tells the Smuxi frontend how many messages it should fetch from the engine when it connects.
This setting has no real influence to Smuxi in standalone mode (no smuxi-server). By default Smuxi fetches 100 messages per chat when connecting to a smuxi-server. If you increase this value, keep in mind that it will increase the time needed to sync with the smuxi-server.
This setting controls which backend will be used to store messages.
By default Smuxi stores all messages in memory (see Volatile).
Originally Smuxi could only keep messages in memory, thus many kept messages means high memory usage. Also if you restart Smuxi all messages will be gone.
This uses the default persistent backend, which is/was Persistent Db4o.
This backend uses a object database called Db4o.
It is known to have issues with high CPU usage and can crash your Mono runtime. We do not recommend to use it. It is in an experimental state and deprecated in favor of the newer SQLite backend (see below).
This backend stores all message in a SQLite database. It is a preview feature but has no known issues.
Requires: Smuxi 0.12 or later
This setting tells how many messages should be kept in memory per chat if Persistency Type was set to Volatile
By default Smuxi keeps up to 200 messages per chat before it removes them. If you increase this value, keep in mind that it will increase the memory usage!
This setting controls how many messages per chat a disk based / persistent backend should retain before it deletes old messages if Persistency Type was set to any Persistent option.
By default Smuxi stores up to 50,000 messages per chat before it removes them. If you increase this value, your memory usage will not increase, but the amount of space needed in your harddisk.