Exchange 2010 SP3 was released yesterday, here is a very quick walk through of the installation process in case you don’t have a test environment to hand.
The whole SP3 installation tool under 30 minutes from start to finish on a vm workstation based SBS 2011 server with 8GB of Ram and a single vCPU. Granted my Exchange database size is small at only a few 100MB, but looking at the release notes unless you are upgrading from the RTM version is shouldn’t take much longer.
Edit: Review the notes on how to install Service Packs and Update Rollups for Exchange here: Exchange 2010 SP3 Update Rollup 1 Installation tips.
1. Download the Service pack from here.
2. Run the Exchange2010-SP3-x64.exe and extract the files.
2a. Stop any Backup Exec services if you have it running locally.
3. Browse to the location where the files are and run setup.exe
4. Click the Install Microsoft Server Upgrade link.
5. Accept the license agreement and click next.
6. Wait for the Readiness Checks to complete.
7. Click Upgrade.
8. Once complete, check the setup log, and click Finish.
9. Finally check the version of Exchange is correct, and email services are working correctly.