Im testing Zimbra for 10K users.
All of them check their email using POP3 every 1 minute.
The pop3 services is delivering the messages really slow. Postfix is Fine.
For example a 4MB attachment is sent in less than 1 second trough postfix, but retrieving it with pop take like 5 minutes.
The server is a HP DL360 with 16GB RAM and Two Dual Core Xeon. The storage its a Hitache with FC. Using Multipath with Round Robin.
Using netstat i see a lot of TIME_WAIT connections, like 1000, and only arround 200 ESTABLISHED POP3.
Im running with 600 POP3 Threads.
Any ideas where to check or i need a bigger machine?