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Q159306: XADM: IS Maintenance Tasks Not on IS Schedule

Article: Q159306
Product(s): Microsoft Exchange
Version(s): 4.0,5.0,5.5
Operating System(s): 
Keyword(s): kbusage exc4
Last Modified: 05-FEB-2002

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The information in this article applies to:

- Microsoft Exchange Server, versions 4.0, 5.0, 5.5 
- Microsoft Exchange 2000 Server 
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SUMMARY
=======

The Microsoft Exchange Server Information Store (IS) has many tasks that run in
the background and perform maintenance-type operations. This article outlines
the maintenance tasks that are not controlled by the IS Maintenance schedule.
For additional information on the tasks controlled by the IS Maintenance
Schedule, click the article number below to view the article in the Microsoft
Knowledge Base:

  Q159196 XADM: Tasks Controlled by the IS Maintenance Schedule

MORE INFORMATION
================

The Information Store process performs the following maintenance tasks:

Background Cleanup
------------------

Background cleanup is the process of reclaiming empty space used by deleted
folders, messages, and attachments. There is a registry variable that controls
the rate at which this task runs (not exposed in the Microsoft Administrator
program):

  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS
  \ParametersPublic\Background Cleanup
  (value in milliseconds)

  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\
  ParametersPrivate\Background Cleanup
  (value in milliseconds)

Event logging is controlled by the following registry settings (also exposed in
the Microsoft Exchange Administrator Program on the Diagnostic Logging tab for
the Private/Public Information Store):

  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS
  \Diagnostics\Private\General\Background Cleanup"

  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS
  \Diagnostics\Public\General\Background Cleanup"

Database Compaction
-------------------

Database compaction is a function of the JET database engine, and is not under
the stores control. There is some amount of online compaction that goes on in
the background, as needed. This process cleans up the space made available by
background cleanup. There are times that compaction will not be able to
efficiently keep up and it will log the following Event ID in the application
log:

  Event ID = 63
  Source = EDB
  Category = General
  Description = MSExchangeIS ((44)) Background Cleanup skipped pages. Database
  may benefit from defragmentation

This Event ID means that an offline defragmentation of the Information Store
database should be scheduled and performed. Offline defragmentation is performed
by using the Edbutil.exe utility with the "/d" option. This process is performed
against each database separately (Priv.edb for the private store, Pub.edb for
the public store). For more information on performing offline defragmentation,
see the Microsoft Exchange Server Administrator's Guide, Chapter 17.

NOTE: In Microsoft Exchange Server, versions 5.5 and 2000, Eseutil.exe replaces
Edbutil.exe. For additional information on using Eseutil, click the article
number below to view the article in the Microsoft Knowledge Base:

  Q182903 XADM: ESEUTIL Command Line Parameters

For more information , see the following Knowledge Base Article:

Storage Warnings
----------------

There is a schedule page for checking user's storage limits, this is located in
the Site's Configuration Container in the properties of the Information Store
Site Configuration object under the Storage Warnings tab. A separate background
thread that is launched according to the schedule page and runs until completion
performs this check.

Periodic Background Activities
------------------------------

This task runs at 10-minute intervals, and has a thread allocated to it for the
duration. It performs a sequential list of tasks much like IS maintenance.

- Re-read Information Store storage quota values from the Microsoft Exchange
  Directory.

- Flush table row counts to the database.

- Flush cached Exchange Server Directory information.

- Re-read per-user Mailbox storage quota values from the Exchange Server
  Directory.

- Perform other miscellaneous store functions.

These tasks, like IS maintenance, do not all run at 10-minute intervals; each
task has its own minimum frequency value, which is usually between 1 and 24
hours, depending on the task.

A number of other background activities happen at scheduled or regular intervals,
such as public folder replication, flushing of cached per user read/unread info,
expiration of unread messages, and so on. In general, these functions allocate a
thread when the task starts and free it when it completes.

Additional query words:

======================================================================
Keywords          : kbusage exc4 
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2 kbExchange2000Search kbExchange2000Serv
Version           : :4.0,5.0,5.5
Issue type        : kbhowto

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