Holy cow…4TB on content DBs. Below is quoted from TechNet:
Content databases of up to 4 TB are supported when the following requirements are met:
- Disk sub-system performance of 0.25 IOPs per GB. 2 IIOPs per GB is recommended for optimal performance.
- You must have developed plans for high availability, disaster recovery, future capacity, and performance testing.
You should also carefully consider the following factors:
- Requirements for backup and restore may not be met by the native SharePoint Server 2010 backup for content databases larger than 200 GB. It is recommended to evaluate and test SharePoint Server 2010 backup and alternative backup solutions to determine the best solution for your specific environment.
- It is strongly recommended to have proactive skilled administrator management of the SharePoint Server 2010 and SQL Server installations.
- The complexity of customizations and configurations on SharePoint Server 2010 may necessitate refactoring (or splitting) of data into multiple content databases. Seek advice from a skilled professional architect and perform testing to determine the optimum content database size for your implementation. Examples of complexity may include custom code deployments, use of more than 20 columns in property promotion, or features listed as not to be used in the over 4 TB section below.
- Refactoring of site collections allows for scale out of a SharePoint Server 2010 implementation across multiple content databases. This permits SharePoint Server 2010 implementations to scale indefinitely. This refactoring will be easier and faster when content databases are less than 200 GB.
- It is suggested that for ease of backup and restore that individual site collections within a content database be limited to 100 GB. For more information, see Site collection limits.
For more information on SharePoint Server 2010 data size planning, see Storage and SQL Server capacity planning and configuration (SharePoint Server 2010).