It seems there is a bug when server got a lot of maps (around 3.000) with Linux client.
In console there is:
Loading maps list...
You are a command flooder man!
3 warnings to kick
Then "/ready" alias is unavailable.
It seems to kill ping too (~190 instead of ~40)
Bug produce with 1.9.3 x86 client and 2.0.1 64 client on this server : qw-dev.net:28001
On this server no problem : lalooz.quakeworld.fr:28001
Others players (probably all with windows client) got no problem.