SQLExS Features & Requirements

Jul 21, 2014 | | Sticky post

SQLExS stands for SQL Exchange Synchronisation. SQLExS is easy to deploy and easy to use, it enables you to access any Exchange item with very basic SQL commands. You can consume Exchange data on the SQL Server and create/modify exchange items from within your T-SQL enviroment, just with an simple insert statement.


  • Central server based (runs as native windows serivce)
  • Synchronizes Exchange folder to SQL table (both directions)
  • Public & private folder synchronization
  • synchronizes in  realtime (it uses push techniques and takes less than 1 second for a single item to be synchronized in both directions)
  • Supports RTF bodies & attachments
  • Supports all item types


All current Windows, Exchange and SQL Server versions are supported. To setup SQLExS you need at least one Exchange and one SQL Server Instance. The SQLExS Service can be co-located on one of the two or hosted on a dedicated Windows System. Here is what you need:

  • Exchange 2010 SP1 or Later (2010 SP3 or later recommended)
  • SQLExS Database:  SQL Server 2005 or later (2008 or later recommended)
  • SQLExS Service: Windows 7 or later (Server 2012R2  or later  recommended)

The footprint of SQLExS in your infrastructure depends on the number of synchronized folders and items. SQLExS itself scales very well into hunderts of folders and millions of items to synchronize.

When you want to keep alot of items (millions) in the SQLExS database, size the database accordingly. The hard cold average numbers based on our experience:

SQLExS Database Storage space usage (average numbers based on real world installations):

Please note, that attachments (as can be attached to most items) are not counted*.

  • 40kb per email (with rich text & html body)    Can be reduced to 6kb with textbody only.
  • 3kb per appointment (meeting, etc)
  • 3kb per task
  • 2kb per Contact (without contact pictures)
  • 2kb per stickynote

Please remember that its easly possible to create much smaller and much bigger items of the above type. These numbers are what we see on average. And it works well for database sizing.

Now, when you have calculated the above number for your enviroment, please add 1MB for every folder in sync. Now add 10% for SQLExS internal database storage.


200 users with ~30 folders each. Planing to sync (and keep) about 2 million mails per year for 10 years:

200 x 30  x 1MB = 6GB

2000000 x 40kb = 153GB

(6GB + 153GB) *1,1 = 174,9GB for one year.

(6GB + 153GB*10) *1,1 = 1689,6GB for 10 years.

Another method that works pretty well: take a look at your Microsoft Exchange Database files and mailbox sizes. When you know how much of the exchange system should be kept inside the SQL Server, you’ll become an idea of the space used by the SQLExS Database.


*For your convenience, here is the number:  avg. space taken per attachement is 106kb in our observations.

Posted in: DEV