The 4 settings affect two different operations – A) where there data is written in real time B) how the data is moved between the tiers after it’s written.  Highest Allocation – New writes for the LUN are directed to the highest tier in the pool that has free space (SSD in your case) During scheduled reallocation, cold data is moved down to lower tiers to free space in the SSD and FC tiers Auto Tier – New writes are written to all tiers based on the free space in the tier (tiers with more free space as a % of total capacity) During scheduled reallocation, Hot data is moved to SSD, Warm data is moved to FC, Cold data is moved to SATA Lowest Allocation – New writes for the LUN are directed to the lowest tier in the pool (SATA in your case) During scheduled reallocation, blocks are moved down to the lowest tiers that have free space No Movement – New writes are written to all tiers based on free space (similar to auto tier) During reallocation, NO blocks are moved for the LUN, they are kept in place after writing  Note: FASTVP will leave 10% of the highest tiers free for new writes after a reallocation  My recommendation has been to pick either Highest Allocation or Auto Tier for the majority of the LUNs in the pool (just use one of these, not both in a single pool). The reason for this is that if you have a single LUN set to Highest Allocation, and the rest set to Auto-Tier, then the one LUN could consume the entire SSD tier leaving no space in that tier for any other LUNs. You can use Lowest Allocation for LUNs that you know don’t need performance. In essense – Use Highest and Lowest, or Auto and Lowest. This way you let FASTVP put the hottest chunks of data into SSD for best performance.  Richard J Anderson
We have FAST pool lun comprised of 5 SATA & 5 FC & 5 SSD drive with 10 TB .  I have multiple Lun Created . At Lun Level under Tiering you have 4 option.  1 Auto-tier , Highest Tier Avialable Option, Lowest Availabel Tier & No Data Movement.  I need more detail on these Tier , so If I have LUN name back up which is lowest priority as far as IOPS concern what is the difference between Lowest Available tier & No data movement . other Question is there any way to monitor this dyanmic data .  Sincerely]  Viral
how FAST works & how to test it ?