Page 19 - Mercury Manual.book

The Mercury Core Module 14
The “Mercury Core Module” Configuration menu option.

Who should use lingering mailboxes? If your clients primarily connect to their mailboxes via
IMAP or webmail, then you should consider enabling this option. If your users mostly use a
local copy of Pegasus Mail to access their mail, and only occasionally access their mailbox
via IMAP, you typically should not enable this option, or should enable it with a short timeout
period. The reason for this is that while the mailbox is in the cache, it remains "in use" and
locked, and local copies of Pegasus Mail will be unable to access the mailbox until the cache
entry times out.

Linger timeout (seconds) The number of seconds a mailbox should be allowed to stay in the
cache without being accessed before it is broken down and removed from the cache. You can-
not set this field to a value lower than 15 seconds, and you should exercise considerable cau-
tion in setting it to any value much greater than about 600 seconds.

Lingering mailboxes and memory A fully-initialized mailbox occupies quite a lot of server
memory (200 - 300KB is typical), and while the mailbox is in the linger cache, that memory
remains allocated. Now, 300KB is nothing on modern systems, but if you have 100 users,
suddenly the number goes up to 30MB, which is starting to get more significant. If you use
lingering mailboxes and have lots of users, make sure you are running Mercury on a system
that has adequate memory.

Options on the Reporting page
One of Mercury/32's most powerful features is its ability to gather statistics about mail flow-
ing through the system. You can view the statistics gathered by the program in real time by
opening the Statistics window using the option on the Window menu: the settings in this page
control other options for saving or posting the statistical information, and allow you to control
the type of information Mercury should display in its System Messages window.

Save statistics to a file periodically If you enable this control, Mercury/32 will save its sta-
tistical information to a file periodically. You supply the name of a directory on your compu-
ter (note that it is a directory, not a filename) and Mercury will create statistics log files in
that directory. Statistics log file names have the format YYMMDDHH.MSR.

E-mail statistics periodically Enabling this control tells Mercury/32 to send out its statistical
information to an e-mail address periodically. The e-mail address need not be local, but it is
a restriction at present that you can only enter a single address here. It is perfectly reasonable
to enable both the file save and e-mail options, usually with different periods — this allows
you to keep as much information about the running of your system as you wish, and to get an
overview of it mailed to you less frequently.

Automatically open the statistics window at startup If this control is checked, the Statistics
window will always be opened when you first start Mercury/32.

Collect statistics about mail sent by local users If you check this control, Mercury/32 will
gather information about the size and number of messages sent by each user on your system,
presenting them in a statistics window section called User statistics - sending. This setting is
an option because it can consume a significant amount of memory on your system if you have
many users, but it is an extremely useful way of tracking usage patterns on the server.

System messages These options control the way the Mercury/32 System Messages window
behaves. The System Messages window (opened using the option on the Window menu) acts
as a kind of console on which the various modules in the system can report information of
varying kinds to you. Modules will typically give each message they generate a priority val-
ue, indicating how significant it is: you can control the significance level you want Mercury
to display using the first control, System message reporting level. There is usually no reason