Free Disk Space Monitor
The low-space warning or Free Disk Space Monitor is designed to warn system administrators that the amount of free space available to Mailtraq is too low for safe operation. Introduced in build 2156 .
Warning emails are sent to the designated address when an outer limit is reached. At this time the prudent operator should review their mail storage capacity and message retention rules to ensure there is enough disk space for safe continued operation of mail services.
By default warning messages are sent to the admin user. You can change that to a specified local user - as in the example shown
If the warning emails are ignored and available free space falls to below a safe level Mailtraq will suspend mail services to force the system administrator to attend the Console so that they are aware of the situation.
Suspension notices are also written into the Mailtraq Event Log.
[Date] [Time] SMTP: (Suspended) Denying connection to [IP Address]
[Date] [Time] IMAP: (Suspended) Denying connection to [IP Address]
This dialog is located in the Console, under Options | Server, Logs-tab
Mail services can be enabled by removing the
check-marks in the dialog boxes,
and then [OK] back to the Console.
The Monitor will then be disabled and must be manually re-enabled.
Why has Mailtraq introduced the Free Disk Space Monitor?
We have received a lot of feedback from users about the way email server usage has changed in recent years. The acceptance of IMAP and webmail for sharing messages, the requirement for statutory retention of messages and the use of calendaring and address-book services have all meant that mail servers now hold much more data than they used to.
Mailtraq holds all of the essential information within a database, and provides Online Backup facilities to ensure that there is protection against corruption, but for Mailtraq to work effectively there must be sufficient room on the drive for safe operation.
Mailtraq provides two levels of protection against running out of disk space. At first Mailtraq will send an email to the admin (default) or other designated user warning them that disk space is getting tight - less than 200% of the database size. This level was chosen to give ample warning for Administrators to either revise their message retention policy or to obtain more storage space.
The second level of protection is to suspend mail services when free space falls below 110% of the database size. This level was chosen to allow enough space for the Administrator to do a manual copy of the database should it be necessary for a disaster recovery.
Why Suspend mail services?
If the database completely runs out of space on the disk, serious corruption can occur. Mailtraq suspends the mail services to force the Administrator to attend the console and acknowledge the situation. The view was taken that it is much better to have a minor inconvenience rather than a potential serious problem.
No messages will be lost because of the suspension.
I have plenty of free space - and still was suspended !
Mailtraq cannot always accurately determine how much free space there is available - so there may be situations when you receive a report or suspension when there is plenty of free space. In this case, simply disable the monitor but remain aware of the issues.
Updated: 25 July 2012
This monitor is provided as an aid to the Administrator of the email server, but it should not be used in place of prudent management. Mailtraq cannot know what other demands may be placed on the disc space of the machine.