 |
If you have specific questions that are not currently answered within the FAQs, please send an e-mail
to
L8support@lucid8.com and we will be happy to assist you. |
Microsoft Exchange built-in maintenance overview.
Listed
below is a high level overview of the issues every Exchange database
experiences, as well as what the built in maintenance and background
processes accomplish and what needs to happen next in order to ensure
the Exchange databases are properly maintained.
The Exchange databases are constantly growing due to messages,
meetings, Distribution, task, recurring task list etc.
When a user deletes a message, appointment or other item its first
stop is the "Deleted Items" folder specific to that user. Until the
user
empties the deleted items container the items still exist and can be
reclaimed.
When an item is removed from the "Deleted items" folder then from
the users perspective it is truly deleted. However the item has only
been marked for deletion and in reality still exists in the Exchange
database.
While it would seem logical that once an item is flagged for
deletion the item should truly be removed however this is not the case.
Therefore a system with a 10Gb database may actually only have 6Gb of
valid data and the rest of this is wasted white space with items flagged
for deletion.
As new messages arrive in the database, Exchange inserts the
message headers at the end of the binary tree. However, users
continually delete items throughout the tree. Over time, user deletions
cause data pages to become less full and Exchange performance will
steadily degrade.
Exchange's Online Maintenance Process:
In Exchange Server 5.5, 2000, 2003 and 2007 information
stores requires periodic online maintenance to be run against each
messaging database. By default, each messaging database runs online
maintenance between the times of 1:00 AM, and 5:00 AM Online
maintenance performs a variety of tasks that are necessary to keep the
information store in optimal condition.
NOTE:
You will want to ensure that Online Maintenance is running to completion.
If online
maintenance does not complete by the end of the information store
maintenance schedule, the current location is recorded, and the
next online defragmentation begins at this point.
You should
check your Application event log for the ID's specified below. If
for some reason you see a start Event ID but not the Event ID that
designates completion ( Event ID's listed below) within the same day and
or at least no more then a few days later then you should investigate as
soon as possible. It may be that there is a serious issue with the
db's or it could be something as simple as your backup window may be
conflicting with the online maintenance, or you may want to consider
widening your online maintenance window.
Exchange 5.5 Event
ID's:
Event ID 179 signals the beginning of and OLD and Event ID 180
will show when its complete. You will also see an event ID 1206
and 1207 that signifies garbage collection however you want to look
for an Event 1221 in the Windows NT Application Event log soon after you
see Event ID 180. In short look for 179, then 180, 106 and 1207 and finally 1221.
If these events are present online maintenance has taken place.
Exchange 2000/2003 Event ID's:
Event ID 700 signals the
beginning of a full pass, and event ID 701 signals the completion of a
full pass
NOTE:
Exchange Server online defragmentation does not run during a backup
session.
-
Because a backup
program is running during the scheduled information store maintenance,
it is possible that the online defragmentation process may never
complete.
-
For large message
stores, ensure that information store maintenance gets at least five
hours each night that do not overlap with the backup schedule to finish
its tasks.
Each day Online Maintenance does the following;
- Scans the items marked for deletion within the database and if the
age of the deleted item is greater than the number of days set in the
Deleted Item Retention Schedule the item is de-linked from the table in
the database.
- Exchange performs best when it views folders in chronological
order, so online maintenance re-orders and stores message headers close to one another
on data pages in chronological order.
- User deletions gradually empty the data pages, which become
candidates for reuse only when they are completely empty. To free up
data pages, Exchange's online maintenance continually shuffles data from
one page to another.
- Over time, page merging creates a number of empty pages with
de-linked items, known as white space in the database. White space
increases the size of the database, which takes up disk space and slows
not only the general operation of the system and but the backups as well.
What Online Maintenance Doesn't Do:
Offline Maintenance is the only way you can defragment, remove errors and warnings and optimize your
Exchange system. You can use Microsoft's utilities however there are caveats
click here for more information.
Avoid the all the pain and hassle by utilizing GOexchange the complete and only automated
maintenance process for Exchange 5.5, 2000, 2003 and 2007.
Go back to
Why Buy GOexchange if Exchange already contains a built-in maintenance routine
|
Contact Us
Print
Page
