FIGURE  7-1 Sun Message Store Property Book

Sun Message Store Topics and Tasks

TABLE  7-1   Message Store Topics and Tasks

Topic/Task	Description	Page
Enabling APOP	Encoded password for POP connections.	157
Enabling POP Before SMTP	POP3 login required before messages can be sent via SMTP.	157
Message Store Support for Failover LDAP Hosts	How to configure failover LDAP hosts for the message store.	157
Message Store Configuration Backup and Restore	Back up and restore configuration of the message store.	158
Monitoring the Sun Message Store	Describes how to view the SIMS message store path, space usage, and user space quotas.	160
Message Store Quotas	Describes the SIMS user message store quota system.	162
Configuring Advanced Options	Describes the following: - User quota enforcement/default message quota - Disable or enable proxy server - Setup proxy server capabilities - Mail server client type - Maximum connections permitted - Percentage space left warning threshold - /var/mail support - Size by which to increase Sun Message Store - Message purge options and scheduling	167
Message Purge	Discusses how to configure message purge options and purge schedules.	172
Message Access Protocol Connections	How to view and monitor all user connections to SIMS, as well as start and stop client access to the message store	176
Sun Message Store Maintenance	This section is in Chapter 11, "SIMS Periodic Maintenance Procedures." It describes the following Sun Message Store maintenance procedures: - Recommended Maintenance Schedule - Message Purge - Message Store Backup and Restore - Message Store Data Check - Importing /var/mail Users - Deleting Old Messages - Deleting the User	234
Message Access Protocols Error Messages	Error messages and proper responses. Appendix D, "Error Messages."	342

Enabling APOP

Utility: apop

APOP is a POP command that the mail client can use as an alternative to
USER/PASS (RFC 1939). Unlike USER/PASS, APOP does not use the user's plaintext password for authentication. It instead uses an encoding of the password together with a challenge string. For instructions on how to enable APOP on the server see the man page.

Note that if APOP is not enabled, server will respond with Err not supported, if asked to do APOP. To authenticate a user with APOP, their password must be available in plaintext. If it isn't then the authentication will not succeed and they will have to login using the USER/PASS sequence. For instructions on how to enable this feature, refer to the apop man page.

Enabling POP Before SMTP

Utility: popb4smtp

POP before SMTP (popb4smtp) is a mechanism for allowing only users who successfully log in to a POP3 account to send messages via SMTP. popb4smtp is useful for preventing the sending of Unsolicited Bulk Email (UBE) through anonymous SMTP connections. For instructions on how to enable this feature, refer to the popb4smtp man page.

Message Store Support for Failover LDAP Hosts

The message store uses the LDAP directory to authenticate users logging onto the system to access their mailboxes. The name of the LDAP server used for authentication is specified with the ims-ldap-server parameter in the
/etc/opt/SUNWmail/ims/ims.cnf file. If no value is specified, the default is the local host.

You can also specify failover directory servers for the message store. If one LDAP host is not working, the message store will try the next LDAP host. The following line from the ims.cnf file shows how to specify multiple LDAP failover hosts:

ims-ldap-server:host1, host2, host3

host1, host2, host3 are the failover LDAP hosts. You can also specify a port number corresponding to a failover LDAP host as follows:

ims-ldap-server:host1, host2:port2, host3:port3

If no port is specified, the default port of 389 is used. Make sure that the LDAP server on each of these hosts is listening to the specified port.

Two ims.cnf timeout parameters are associated with the LDAP server failover feature:

ims-ldap-failover-timeout - Number of seconds to successfully bind to a given LDAP server before trying the next server on the list. The default value is 30 seconds.

ims-ldap-request-timeout - Cumulative number of seconds to successfully open and bind to at least one of the LDAP servers before generating an error message. This value is also the timeout for doing an ldap_search(). The default value is 60 seconds.

Message Store Configuration Backup and Restore

After SIMS is installed and you have responded to prompts for various information during the initial setup of the server, the server saves or backs up the Sun Message Store configuration. This configuration version is known as the default configuration.

Subsequently, the Admin Console enables you to back up your Sun Message Store configuration at any time. The Admin Console enables you to save up to two versions of the Sun Message Store configuration. The latest working configuration is known as the current configuration. The previously saved working configuration is known as the backup configuration.

For example, imagine that you reconfigure certain aspects of the Sun Message Store using the Admin Console. You decide to back up this particular configuration on May 1. Because this configuration is the latest working configuration, it is considered the current configuration. On June 1, you reconfigure more aspects of the Sun Message Store and perform another backup. The May 1 configuration becomes the backup configuration and the June 1 configuration is considered the current configuration. On August 1, you reconfigure even more aspects of the Sun Message Store and perform another backup. Because the Sun Message Store can save only two configuration versions, the May 1 configuration is not saved. The June 1 configuration becomes the backup configuration and the August 1 is considered the current configuration.

If for some reason you wish to use a previous Sun Message Store configuration version, you can restore one of the following configuration versions:

Default configuration

Backup configuration (provided that this version exists)

To Back Up and Restore the Sun Message Store Configuration

AdminConsole>Sun Message Store Pulldown>Backup config

Monitoring the Sun Message Store

To Monitor Mail Store Space Usage and Settings	160
To View Sun Message Store Paths	161
To Monitor User Quotas	165

To Monitor Mail Store Space Usage and Settings

You can monitor the following Sun Message Store parameters:

Current size of the directories that store user folders, indexes, messages and attachments, message hash, Sun Message Store log files, and shared or group folders

Amount of remaining hard disk space available for each directory listed

AdminConsole>Sun Message Store>General Options>Message Store Space Usage

FIGURE  7-2 Message Store Space Usage Subsection

Path - Directory that stores user folders, indexes, messages and attachments, message hash, Sun Message Store log files, and shared or group folders

Device - Hard disk partition on which the directories reside

Size - Current size in kilobytes of each directory

Available - Amount of remaining hard disk space currently available for each directory

To View Sun Message Store Paths

During SIMS installation, you provided a path name for the directories that store the messages and attachments, indexes, user folders, shared or group folders, message hash, and log file, or you decided to use the default path names. Values for owner, host, and number of days were also assigned during installation. These can be viewed with the following procedure. Of the values displayed in this section, you can reconfigure the number of days to initialize the Sun Message Store only. For more information, refer to "Sun Message Store Increase" on page 169.

AdminConsole>Sun Message Store>General Options> Store Paths

FIGURE  7-3 Store Paths Subsection

IMS Owner - Owner (of Sun Message Store files).

IMS Host - Name of host on which the Sun Message Store is installed.

FileSystem - This can either be logging or nlogging. A logging file system performs logging such that if a system crashes it is possible to roll back the data to a pre-crash state and restore all data. An example of a safe file system is VXFS. An nlogging file system does not perform logging. If the system crashes, the state cannot be recreated and some data may be lost. You must also perform an imcheck before activating message access to these files.

User folders - Contains user's email folders.

Shared Messages - Contains folders for shared folders.

Message Databases - Contains messages and attachments.

Message Indices - Contains message index files.

Message hash - Contains hashing files.

IMS Log - Sun Message Store log files.

IMS initialization duration in days - Number of days to initialize the Sun Message Store.

Message Store Quotas

Mail Store Usage Calculation	163
To Activate Message Store Quota Enforcement on an Installed System	163
To Set a User's Mail Store Quota	164
To Monitor User Quotas	165
To Warn Users When Their Mail Store Usage Is Approaching Their Mail Store Quota	166
Setting Soft Quotas	167
Problems Turning Message Store Quota Enforcement Off and On	276

SIMS allows administrators to limit the amount of mail storage allocated to a user. This limit is called the message store quota. Once this feature is enabled, the system calculates the amount of disk space occupied by a user's messages. If the amount exceeds the quota specified for that user, further mail is bounced back to the sender and no further mail can be received by this user until the quota is increased or the user deletes some messages in the mailbox. Note that message store quotas can only be used with the Sun Message Store. This feature will not work with /var/mail.

SIMS also provides a mechanism to warn users and administrators when their mail store usage approaches their quota. Refer to "To Monitor User Quotas" on page 165.

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Note - Quotas can only be set to users and not domains. SIMS provides a mechanism for monitoring the amount of space used by a domain, however, mail to a domain will not be bounced.

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Mail Store Usage Calculation

Mail store usage is calculated by totaling the space usage of all the messages in all the user's mailboxes. If a message is sent to multiple users, SIMS adds the message size to the user's total usage--even though the message is only stored in one place with each user having a pointer to it.

To Activate Message Store Quota Enforcement on an Installed System

When SIMS is installed, the message store quota feature is set to OFF. This means that user's mailboxes can occupy an unlimited amount of mail storage space. Implementing a message store quota involves the following steps:

As described in the above procedure, there is more than one way to enable the various quota options. TABLE 7-2 shows the action required to implement the desired option.

TABLE  7-2   Message Store Quota Option-Action Matrix

Option	Admin Console	ims.cnf	LDAP Directory
Activate SIMS quota checking	Set User quota enforcement to ON in Sun Message Store Property Book, Advanced Options. (See "To Configure Advanced Options" on page 170)	Set ims-quota to ON.	Not Available
Set system default quota	Set Default User quota enforcement to ON in Sun Message Store Property Book, Advanced Options. (See "To Configure Advanced Options" on page 170)	Set ims-default-quota to <size-of-quota-in-bytes>	Not Available
Set user quota	In the user's property book entry select either Default User Quota, No Store Limit, or Set Individual Quota. See "To Modify a User Entry" on page 41)	Not Available	Set MailQuota to -1 (no limit), -2 (default quota) or N (N=quota in bytes)

To Set a User's Mail Store Quota AdminConsole>User Manager>Display then double click the user entry>Mail Information

Use Default User Quota - This option allocates the amount of storage specified in the Default User Quota set in the Message Store Property Book. (MailQuota = -2. If there no MailQuota attribute, the system defaults to -2).

No Store Limit - This turns off the message quota feature giving this user unlimited message store space. (MailQuota = -1)

Set Individual Quota - Select a number and the unit of measure (kilobytes or megabytes). This quota will not take effect until an incremental or full directory synchronization occurs (see "Alias Synchronization Schedule" on page 87 or see the dirsync, iminitquota, and imquotacheck man pages for more information). MailQuota = <Size of Quota in Bytes>.

To Monitor User Quotas

Utility: imquotacheck

SIMS allows you to monitor the amount of disk space used by individual email users as well as domains using the imquotacheck command. You can also automatically send warning message to users whose space usage is approaching their message storage quota. Refer to the man page for further details.

Use imquotacheck -v (verbose)

The User Quota page displays as follows:

--------------------------------------------------------------------------- Domain : eng.sun.com Max Mailboxes : NO LIMIT --------------------------------------------------------------------------- Username | Quota(byte) | Total(byte) | % used | Status --------------------+-----------------+-----------------+--------+--------- siteadmin | NO LIMIT | 0 | NA | NORMAL deladmin | NO LIMIT | 0 | NA | NORMAL boverby | 20000000 | 3069 | >0% | NORMAL katho | NO LIMIT | 138269718 | NA | NORMAL davidx | 20000000 | 7879082 | >39% | NORMAL gherman | 20000000 | 19999820 | >99% | ALERT mcintosh | 0 | 35662057 | >100% | ALERT mfang | NO LIMIT | 21967034 | NA | NORMAL --------------------------------------------------------------------------- Total Usage for eng.sun.com : 223780780 Bytes ---------------------------------------------------------------------------

User name - Name of each Sun Message Store user sorted alphabetically. Use the scroll bars to view the entire list.

Quota - Maximum amount of hard disk space that can be used in kilobytes.

Total - Amount of hard disk space used in kilobytes.

Used - Amount of hard disk space used in percentage.

Status - ALERT indicates that the user has exceeded 85% of the quota.

To Warn Users When Their Mail Store Usage Is Approaching Their Mail Store Quota

The imquotacheck command sends an email warning to users who are approaching their mail store quota. This command can be put in a cron file to provide a daily check on mail store users. You can configure the desired warning message using the -f flag. See the man page.

Setting Soft Quotas AdminConsole>Sun Message Store>Advanced Options>User quota enforcement

When a hard quota is exceeded, no more messages will be accepted into the message store until the message store size is reduced. To set a hard quota, follow the instructions in "To Activate Message Store Quota Enforcement on an Installed System" on page 163.

When a soft quota is exceeded, messages will be accepted into the message store, but a message is generated and sent to the user saying that their quota has been exceeded. To set a soft quota:

Configuring Advanced Options

To Configure Advanced Options

170

The following is configurable in the Advanced Options section:

User quota enforcement/default message quota

Mail server client type

Maximum connections permitted

Warning threshold for percentage space remaining

/var/mail support

Size by which to increase Sun Message Store

Purge schedule

The following sections provide background information on each of the options that will help you decide if you want to configure them.

User Quota Enforcement

By default, each SIMS user has no maximum amount of hard disk storage or quota that they can use for their mailboxes. They can use an unlimited amount of disk space for their incoming and stored messages. SIMS allows you to configure a quota for each Sun Message Store user. If you decide to implement user quotas, you can set a customized quota for each user, or you can set the default quota for a user. The default quota, which can also be changed, is 20 Mbytes. For complete details see "Message Store Quotas" on page 162.

Mail Server Client Type

The Sun Message Store handles the parsing of messages for Internet Mail Access Protocol version 4 (IMAP4) clients and Post Office Protocol version 3 (POP3) clients in different ways. IMAP4 messages are preparsed and indexed when inserted into the Sun Message Store; no parsing is necessary when messages are accessed by mail client users. POP3 messages do not require parsing; therefore, the Sun Message Store does not parse these messages.

By default, the Sun Message Store treats all messages as messages from IMAP4 clients.

Since parsing takes CPU cycles and creates a need for more hard disk space, you may want to tune the amount of parsing that your mail server performs. If a majority of the messages stored by the Sun Message Store are from POP3 clients, you can change the default setting to POP3. The Sun Message Store will treat all messages as messages from POP3 clients and not parse them.

Maximum Connections Permitted

By default, the maximum number of active connections from IMAP4 clients that the Sun Message Store accepts is 10,000. The Advanced Option section in the Sun Message Store property book enables you to expand the maximum number of connections using the maximum connections permitted option. The up and down arrows for this option allow you to select a value in the range of 50 to 2,000,000,000 (billion).

When raising the maximum number of connections, keep in mind that the Sun Message Store daemons reserve shared memory for interprocess communication based on this number. If too high a number is configured, the Sun Message Store fails to allocate sufficient shared memory to handle the maximum number of connections specified. The Sun Message Store will log an error message and exit.

If you attempt to configure the mail server to accept above the maximum number of connections permitted, imaccessd will log a message stating that the maximum connection number was exceeded and that the default number of 10,000 is being enforced.

Warning Threshold for Space Remaining

By default, when the amount of hard disk space for the Sun Message Store is down to 5 percent, you will receive a warning in the System Status section of the Admin Console home page. The Advanced Option section in the Sun Message Store property book enables you to reconfigure the space threshold at which you will be warned.

/var/mail Support

By default, access to mailboxes in /var/mail is not supported. The Advanced Option section in the Sun Message Store property book enables you to reconfigure this default so that users who have mailboxes in /var/mail can access the mailboxes using either the IMAP4 or POP3.

Sun Message Store Increase

The Sun Message Store stores messages using a time-based structure. By default, a data directory contains 30 subdirectories, or one subdirectory for each day of the month. The data directory stores messages and attachments as files. For example, on May 1, all messages that enter the Sun Message Store are stored in the day 1 subdirectory. On May 15, all messages are stored in the day 15 subdirectory.

The Advanced Option section in the Sun Message Store property book enables you to reconfigure the time-based structure in which messages are stored using the Increase Store Size option. For example, if you specify 3 weeks, 21 subdirectories are created, 1 for each day of the 21-day interval. Messages entering the Sun Message Store on the first day of the interval are stored in the day 1 subdirectory and so on.

The distinction between the month and week intervals is that if you specify weeks, the Sun Message Store needs to allocate space more frequently than if you specify months. Modifying this feature has no impact on performance or resources.

To Configure Advanced Options

Configuring these features is optional.

AdminConsole>Sun Message Store>Advanced Options

FIGURE  7-4 Advanced Options Section (Extended View)

Click ON to allow user message store space quotas to be set.

Click OFF to allow users unlimited message store space.

Message Purge

To Configure Purge Options	174
To Configure the Purge Schedule	175

When a message is delivered into the Sun Message Store, a reference pointing to the stored message is created in the inbox of each of the message recipients. As each recipient reads, deletes, and removes (expunges) the message via their respective mail clients, the associated reference to the message is removed. When all references are removed or expired (see "Deleting Old Messages" on page 245), the message can be purged from the Sun Message Store.

Purge messages by manually executing the impurge command (see the man page) or by using the Admin Console to automatically run impurge.

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Note - Do not wait until your disk is full before doing a message purge. Run a message purge while there is more empty disk space than the amount of space used by the mail store on its busiest 24-hour period. You can roughly calculate mail store disk usage by noting the disk usage increase on the /var/opt/SUNWmail/ims partition over a 24-hour period. If your message purge fails due to lack of disk space, refer to "Message Purge Failure" on page 277.

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For additional information on Sun Message Store maintenance, including purge, refer to "Sun Message Store Maintenance" on page 234.

Configuring Purge Options

The Admin Console enables you to configure the following purge options:

Exhaustive purge - Locate all deleted messages that can be purged and purge them. (A deleted message is a message that is no longer referenced by any user or shared folder.)

Customized purge - Perform daily computations to determine if the amount of deleted messages on a given day exceeds a percentage threshold and if the amount of disk space recovered if a purge is performed exceeds a size threshold.

Purging a message store supporting more than 20,000 users could take hours, so for some systems it may be preferable to choose Customized Purge rather than an Exhaustive Purge since fewer purges will be required. Users can still send and receive mail during a purge, but the system cannot delete or expunge messages until after the purge is completed.

Customized Purge

You can customize a policy whereby the purging of unreferenced or deleted messages from the Sun Message Store is performed on an as-specified basis rather than on a daily basis. The customized purge option enables you to set two thresholds: percentage and size.

Percentage is defined as the fraction of deleted messages of the total volume of messages handled by the Sun Message Store on a particular day. Size is defined as the total amount of disk space in kilobytes that can be recovered after deleted messages are purged. The system computes percentages and sizes that are compared against these thresholds daily.

For example, imagine that you have set the percentage threshold to 50 percent and the size threshold to 100 Kbytes. Imagine that on the first day after a purge is performed (day 1), the system examines the total volume of messages handled by the Sun Message Store and the total volume of deleted messages. The system computes the percentage of deleted messages based on the total volume of messages. If the percentage of deleted messages is 51 percent or higher, then day 1 is purged. If the percentage of deleted messages is 50 percent or lower, then day 1 is not purged. Additionally, if the size of deleted messages exceeds 100 Kbytes, then a purge is also performed.

To Configure Purge Options

AdminConsole>Sun Message Store>Purge Options

The Purge Options section appears as shown in FIGURE 7-5.

FIGURE  7-5 Purge Options Section

To Configure the Purge Schedule

For information on Sun Message Store maintenance, including purge, refer to "Sun Message Store Maintenance" on page 234.

No default purge schedule exists. Therefore, if you want to purge or permanently remove messages that no longer have references from any folder on a regularly scheduled basis, you must set a schedule.

AdminConsole>Sun Message Store>Schedule For Purging Deleted Messages

FIGURE  7-6 Schedule For Purging Deleted Messages Section

Message Access Protocol Connections

Message Access Protocols Error Messages

342

FIGURE  7-7 Message Access Property Book

User Name - User name associated with the connection.

Time Stamp - Date and time at which user established connection to mail server.

Protocol - Message access protocol used to make connection.

Host - Host name of machine from which the connection is made. By default this is the IP address of the host machine. You can change this to be the name of the host machine by changing the ims-client-lookup to DNSON in ims.conf. However, changing to DNSON results in the DNS reverse lookup calls made to the DNS server, which can increase the amount of time it takes for clients to login.

Mailbox - Mailbox that user is accessing via the connection. A user can access multiple mailboxes at any given time.

The Statistics area provides the following information:

Date and time at which the connection table is accessed or updated.

Total number of specified connections.

Type of connections that you specified.

FIGURE  7-8 Connection Status