With the introduction of the Cached Exchange Mode in Outlook 2003, Microsoft Outlook has now made it much easier for users to work offline and without the fear of interruptions. However, it can consume a large amount of system resources and to ensure that the entire network operates smoothly, there are some considerations to bear in mind.
The Cached Exchange Mode available in Outlook 2003, 2007 and 2010 is an improved version of the offline folders feature in Outlook but a whole lot easier to use. This allows you to work with your Exchanger Server mailbox even if you are not able to connect to the server or if the connection is interrupted. When you work in the Cached Exchange Mode, you store a copy of the mailbox located on the server, in your local workstation by simply creating an offline folder file or OST file. When you are connected to the Exchange Server, Outlook will download a copy of all the items stored in the mailbox into this OST file and then regularly synchronize the two so that at any point in time, you will find the same items in both the OST file as well as the Server mailbox. The idea is that if you are not able to access the Exchange Server mailbox, you should still be able to recover OST data and work from this on your local workstation.
Obviously, the Cached Exchange Mode is a very valuable feature in Outlook. The only concern for a system administrator is that this feature does tend to consume a large amount of system resources. This makes it necessary for the administrator to carefully evaluate if users should be allowed to use Outlook Cached Mode. Let us look at the two main factors that could have a bearing on the decision.
- Disk Capacity – When the Cached Mode is enabled, users can store cached data on their local hard disks. This means there has to be enough free hard disk space to store the data. Also, one has to track the size of user’s mailboxes. This is necessary for two important reasons. One, once the OST file starts getting larger in size, it starts affecting the performance of Outlook. Secondly, the larger the file size, the greater the chances that the file will get corrupted and one has to use a repair software to recover OST data. If users’ mailboxes are getting too large, it is better to archive older data so that the OST file size stays manageable.
- Network Bandwidth – Given the large amounts of bandwidth available today, you might think that network bandwidth is not such a serious concern. However, it does become a concern at the time of initial synchronization when all the data from the Exchange Server mailbox is being copied into the local OST file. All the subsequent synchronizations copy only the most recent data that has been added or modified in the Server mailbox and do not take up too much bandwidth. The solution would be to stagger implementing the Cached Mode in users’ Outlook so that initial synchronization happens at different times.
While the OST file offers great flexibility, it also leaves users with an orphaned file when the mailbox on the Exchange Server gets deleted accidentally or is damaged due to virus attacks. To recover OST data from an orphaned OST file, it is best to use a specialized tool such as DataNumen Exchange Recovery from DataNumen that can scan and restore data from the file.