27.3.2.2 To Monitor Disk Space

Depending upon the system configuration you may need to monitor various disks and partitions. For example, MTA queues may reside on one disk/partition, message stores may reside on another, and log files may reside on yet another. Each of these spaces will require monitoring and the methods to monitor these spaces may differ.

Messaging Server provides specific methods for monitoring message store disk usage and preventing partitions from filling up all available disk space.

You can take the following steps to monitor the message store’s use of disk space:

• Set parameters to monitor message store disk usage

• Lock message store partitions when a disk-usage threshold is reached

For details, see the sections that follow: Monitoring the Message Store and Monitoring Message Store Partitions.

Monitoring the Message Store

It is recommended that message store disk usage not exceed 75% capacity. You can monitor message store disk usage by configuring the following alarm attributes using the configutil utility:

• alarm.diskavail.msgalarmstatinterval

• alarm.diskavail.msgalarmthreshold

• alarm.diskavail.msgalarmwarninginterval

• alarm.diskavail.msgalarmdescription

By setting these parameters, you can specify how often the system should monitor disk space and under what circumstances the system should send a warning. For example, if you want the system to monitor disk space every 600 seconds, specify the following command:

configutil -o alarm.diskavail.msgalarmstatinterval -v 600

If you want to receive a warning whenever available disk space falls below 20%, specify the following command:

configutil -o alarm.diskavail.msgalarmthreshold -v 20

Refer to Table 27–6 for more information on these parameters.

Monitoring Message Store Partitions

You can halt messages from being delivered to a message store partition when the partition fills more than a specified percentage of available disk space. This is done by setting two configutil parameters to enable the feature and specify the disk-usage threshold.

With this feature, the message store daemon monitors the partition’s disk usage. As disk usage increases, the store daemon dynamically checks the partition more frequently (ranging from once every 100 minutes to once a minute).

If disk usage goes higher than the specified threshold, the store daemon:

• Locks the partition. Incoming messages are held in the MTA message queue, but not delivered to the mailboxes in the message store partition.

• Logs a message to the default log file.

• Sends an email notification to the postmaster. (You can change the recipient of the email by setting the configutil parameter alarm.msgalarmnoticercpt.)

When disk usage falls below the threshold, the partition is unlocked, and messages are again delivered to the store.

The configutil parameters are as follows:

• local.store.checkdiskusage enables the partition-monitoring feature.

  Allowable values: yes, no

  Default value: yes

• local.store.diskusagethreshold specifies the disk-usage threshold. The value of local.store.diskusagethreshold is a percentage from 1 to 99.

  Default value: 99

You should set the disk-usage threshold to a percentage low enough to give you time to repartition or assign more disk space to the local message store.

For example, suppose a partition fills up disk space at a rate of 2 percent per hour, and it takes an hour to allocate additional disk space for the local message store. In this case, you should set the disk-usage threshold to a value lower than 98 percent.

Monitoring the MTA Queues and Logging Space

You will need to monitor MTA queue disk and logging space disk usage.

For information on managing logging space, see Chapter 25, Managing Logging For example, to learn how to monitor the mail.log file, see 25.3 Managing MTA Message and Connection Logs