How can you calculate how much performance overhead you will encounter with sub-LUN auto tiering?
However, it is worth noting that when you start using auto-tiering software, it must perform some data gathering and analysis before it starts performing the tiering operation. I have seen this take anywhere from a few minutes to 24 hours, depending on the system and workload. This is lower than initial implementations that could take upwards of two weeks.
The longer that data is collected and analyzed, the more efficient the software becomes when moving data to the appropriate performance level.
This was first published in October 2013