Ref: 13420003
Title: 3+Mail Can Lose Messages if CIOSYS File Parameters Are Set Low
date: 8/30/89

Copyright 3Com Corporation, 1991.  All rights reserved.

Users of 3+Mail may lose messages when a mail server's CIOSYS
file handles and descriptors are set below the recommended
values.  3+Mail loses the messages because there are no file
handles and descriptors available to handle a request to send or
retrieve the mail message.  If sending a message, the workstation
may lock up and the message will be lost.  If retrieving
messages, the workstation will show that it is checking for mail
or that the mail server is not responding; upon rebooting, the
pending messages will be lost.

To avoid this situation, set the number of the handles and
descriptors high enough to handle the number of users who are
accessing the server.  The recommended formulas for these two
parameters are

              File Handles = 7 * (Active Users)
              File Descriptors = 5 * (Active Users)

You may have to set the values higher if the mail service is
supporting many users and 3+Share is also used on the server.
Realistically, a mail server should support no more than 200
users even though the 3+Mail service can be configured for more.
If your network is very large, consider distributing the services
between more servers rather than making one server support all
the mail users.
