OL98: (CW) Purpose and Capacity of Outlook Storage Facilities (181406)
The information in this article applies to:
This article was previously published under Q181406
NOTE: These procedures only apply if you have installed Outlook with the Corporate Workgroup/Other option. This option allows you to use Messaging Application Programming Interface (MAPI) services. To determine your installation type, on the Help Menu click About Microsoft Outlook. In
About Microsoft Outlook you should see "Corporate" if you have the
Corporate or Workgroup installation.
SUMMARY
This article discusses the purpose and capacity of each of the following
storage facilities used by Microsoft Outlook 98 when running as a client to
a Microsoft Exchange Server:
- Personal Folders (.pst) files located on the user's computer.
- Offline Store (.ost) files located on the user's computer.
- Mailbox Folders located on the Microsoft Exchange Server.
- Public Folders (PF) located on the Microsoft Exchange Server.
MORE INFORMATIONPersonal Folders Files Located on Your Computer
One or more .pst files can reside on each user's computer. A .pst can be defined as your primary store or as a secondary store. A primary store means that mail delivered to the Inbox in that file and all of your other default Outlook folders, such as Calendar, Contacts, Deleted Items, Journal, Notes, Sent Items, and Tasks reside there. A .pst file can also be defined as a secondary store, which means you can move items to that file, either manually or with Inbox Rules, from your primary store.
Each .pst file can contain 16,384 items. An item is either a folder, message, task, etc. Each folder can contain a maximum of 16,384 items.
If you select the option to "Allow upgrade to large tables," each folder can contain up to 65,536 items. The total file size of a .pst cannot exceed 2 Gigabytes (GB).
Offline Store Files Located on Your Computer
Only one .ost file can reside on each user's computer. The .ost is always
defined as your primary store, meaning that your mail is delivered to the
Inbox in that file and all of your other default Outlook folders, such as
Calendar, Contacts, Deleted Items, Journal, Notes, Sent Items, and Tasks
reside there. The .ost differs from the .pst in that items residing in it
can also reside in the Mailbox on the server. You can synchronize the .ost
and Mailbox folders so that they always contain the same information. This
allows you to work offline when the server is unavailable; then when
reconnected to the server, changes made offline will be uploaded to the
server and then mail received while offline downloads to the .ost.
The .ost file can contain as many root folders as you desire and each
folder can contain a maximum of 16 KB subfolders. If you select the option
to "Allow upgrade to large tables," each folder can
contain up to 64 KB subfolders. The total file size of an .ost cannot
exceed 2 GB.
Mailbox Folders Located on the Microsoft Exchange Server
A Mailbox Folder for each user is stored on the server in the same
database store. The server has a capacity of 16 GB for one store, however
the server administrator may limit the size of each user's Mailbox Folder.
Note: this limitation does not apply to the Enterprise edition of
Microsoft Exchange Server version 5.5. Store sizes are restricted to drive
space installed and available on the server. If larger capacity drives are
installed on the server, the stores can grow to the size available. This
is not true of the Standard edition of Microsoft Exchange Server, which
has the same store size limits as previous versions.
Public Folders Located on the Microsoft Exchange Server
Public Folders (PF) reside on the server in the same database store. They
contain information shared by many users. Depending upon access
permissions, individual users can read, update, or add to the Public Folder. The server has a capacity of 16 GB for one store.
REFERENCES
For more information about this subject, please see the following articles
in the Microsoft Knowledge Base:
182158
OL98: (CW) What Are Offline Folders and How Do You Use Them?
182062
OL98: Working with Personal Folders
156077
XADM: How to Specify Where New Public Folders Are Stored
149217
XCLN: Microsoft Exchange Message Size Limitations
143376
XADM: Storage Capacity Limits of Microsoft Exchange Server
Modification Type: | Major | Last Reviewed: | 12/2/2000 |
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Keywords: | kbinfo KB181406 |
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