We have quite a number of SQL Servers that need to be upgraded from version 2005 to 2008 R2. Work is planned before the middle of the year as Microsoft is ending its support for the same.
The 2005 SQL Servers are all SP3 and SP4, running on Windows Server 2003 (whose support has already ended, but we have exception of extension for one more year), but where required we might go with a server OS upgrade as well.
These servers include replication (transactional), log shipping, reporting services, and an integration server running SSIS packages.
My question here is not how, rather I would like to know the risks involved or any pre-checks that can be done before planning this upgrade?
Also, will an in-place upgrade be a better plan than side-by-side for this migration/upgrade?