I have been working with customers on upgrades and figured I would provide you with some of the notes about Database growth. As we upgrade the databases they will grow (Talking about mdb, ldf, and log files) this happens because the schemas change and they have to move columns around and massage data. The space can be retrieved and for the health of sql you really should after the migration of the database is complete as it is mostly white space.
Here are some of the notes with my customer the first is general info and the second is an anlyze based on there dataset.
Recently during one of our discussions I had mentioned that the database will grow during migration, I have found some supporting info with some recommendations.
Plan for databases and logs to grow by 50% each (This includes the Temp DB). This is due to the conversion of the database schema.
We can retrieve that space post migration by performing a DBCC Shrink on each database. Normally I do not recommend this since we have taken the performance hit on the growth we may as well keep it, however in this case it will be fairly dramatic and I think it is more responsible to return the drive space.
Upgrading to Microsoft SharePoint Server 2010
Once the migration is done we can return the unneeded drive space. If we want we can also limit the amount of drive space that we need by migrating only a certain number of databases at a time (ie Migrate 10 then perform shrink, than migrate another 10, etc.
So this is what I understand and my recommendations, please correct me if I got anything wrong.
Data drives are total of 4TB with 700GB free
Log/Backup drive is 2.5TB with ~300GB free
Temp DB and Logs for it are stored on 200GB drive
Current Content Database dataset is ~2.8TB
For migration we would need ~4.2TB of drive space for the data files. We will be able to shrink the databases by ~1.4TB once migration completed.
For Growth, if we want to plan for 2 years without any better metrics I would suggest using 10% growth per year we can expect our data to grow by ~309GB
Data drives: 3 x 2TB drives, we will split the data evenly across all 3 drives then upgrade databases. Once done we shrink our databases, and split all data across 2 x 2TB returning the 3rd one as we don’t need it for Production (This is of course if we are able to do this).
Log Drive: 1 x 500GB
Temp DB: 1 x 200GB, please review this article for Best Practices around Temp DB and SharePoint http://technet.microsoft.com/en-us/library/hh292622(v=office.15).aspx
Backup Drive: 1 x 2TB