Tips for tuning mail performance

Controlling message delivery

You set delivery controls in the Configuration Settings document on the Router/SMTP > Restrictions and Controls > Delivery Controls tab, under Delivery Controls.

Maximum delivery threads

This setting determines the maximum number of threads the Router can create to perform local mail delivery. Increasing this value can improve message throughput for local deliveries. The ideal number ranges from 3 to 25. This is determined by a formula, based upon the NSFBufferPoolSize. You can increase or decrease the value based on the server configuration. Monitor Mail.Waiting over a period of time. If there is a backlog over a period of time, increase the number. Monitor Mail.Delivery.Threads.Total. If the value is less than Mail.Delivery.Threads.Max, set the value to the total.

Setting transfer limits

You set transfer limits in the Configuration Settings document on the Router/SMTP > Restrictions and Controls > Transfer Controls tab, under Transfer Controls.

Maximum concurrent transfer threads

This setting determines the maximum number of concurrent transfer threads per destination. The default is the value entered for Maximum transfer threads divided by 2.

Maximum transfer threads

This setting determines the maximum number of threads the mail Router can create to perform mail transfers. Without this variable, the default is one thread per server port. Increasing this number creates more threads to handle mail transfers. However, additional threads may increase the demand for server processing time.

Setting the number of mailboxes

If there are a small number of users on a server, the default (1) is usually sufficient. For larger numbers of users, you can create multiple MAIL.BOX databases by setting the number to 2 or higher. To determine the optimum number, enter SHOW STAT MAIL at the server console. If MAIL.WaitingRecipients is large or increasing, adding a mailbox may improve performance if the server resources are not overloaded.

You set the number of mail.boxes in the Configuration Settings document on the Router/SMTP > Restrictions and Controls > Basics tab. Under Router/SMTP Basics, enter a value for Number of mailboxes.

Setting IMAP session time-out

If the server supports IMAP users and has limited resources, it may free up server resources and improve performance to set this to a value of 30 minutes or more.

MinNewMailPoll

This setting determines how often workstations can contact the server to see if new mail has arrived for the user. This setting overrides the user's selection in the Mail Setup dialog box. You can increase the mail polling interval if there are a large number of mail users on your server and you want to prevent frequent polling from affecting server performance.

NoMsgCache

This setting disables per-user message caching by the IMAP task. This can improve capacity (number of users) on a server by reducing memory consumption. However, response time for some user operations may be slower.

POP3_Config_Update_Interval

This setting determines how often (per minute) the Domino® server that runs the POP3 service updates its configuration information. The default is 2 minutes.