Why is my OST file so big?

A point worth noting, I think …  Say your Mailbox as reported in Exchange Management Console/Shell/ESM is 110 Mb, an often asked question is why the OST file for that mailbox is soooo much bigger.

Microsoft have the answer : http://office.microsoft.com/en-us/ork2003/HA011402591033.aspx

<snip>

When deploying Cached Exchange Mode for Outlook, be aware that users’ OST files can increase in size by 50 percent to 80 percent over the size of the mailbox reported in Exchange Server. The format Outlook uses to store data locally for Cached Exchange Mode is less efficient than the server data file format, resulting in more disk space used when mailboxes are downloaded to provide a local copy for Cached Exchange Mode.

</snip>

And further..  Remember the OST/PST “speed up” patch which was released.  It had a small side-effect :

http://beqiraj.net/post/Outlook-2007-PST-and-OST-files-may-be-up-to-20-percent-larger.aspx

Hope that’s interesting !

Strange issue with Outlook Web Access 2007

I have a mixed Exchange 2007 and Exchange 2003 environment.  In the environment I have :-

* An Exchange 2003 mailbox server

* An Exchange 2003 front-end server

* An Exchange 2007 CAS

* An Exchange 2007 mailbox server

The 2007 CAS runs Exchange 2007 SP 1.  From a client machine accessing the Exchange 2007 mailboxes using Outlook Web Access access to public folders is working.  When I click on a Public Folder which is hosted on the Exchange 2003 world, then I get some text in the right hand page saying :-

Click here to open this folder with Microsoft Exchange 2003 Outlook Web Access

When I click that link I was getting a page saying : 501 & 505…

HTTP 501 Not Implemented/HTTP 505 Version Not Supported

Further if I go to https://cas/public, I actually get redirected to https://cas/owa.

The issue is “resolved” by updating the mailbox server to Exchange 2007 SP 1.