Disk sizing and data storage

A number of storage-related questions must be answered when setting up the Historian. They include:

• How important is the data? Is it acceptable that four weeks of data is stored online and is then over-written?

• How important is the configuration and event data? This type of information is stored in the Microsoft SQL Server database.

• How often is data in the Microsoft SQL Server database changing?

• Is anyone in the organization going to require operating data that is older than a month? Older than a year?

• How much is the SQL Server component of the Historian expected to be used (for example, for the event system)?

• How long can the system be offline because of a component failure?

• What happens if the system stops storing data?

• What happens if stored data is lost because of a hard drive failure?

• Can the server equipment be taken offline to perform repairs?

Ask yourself questions like these to help you determine disk space requirements and how you should plan to protect your data.

A performance report for different historian systems is provided in System sizing examples.