American Megatrends StorTrends 1300 User Manual page 218

Having chosen the right block to move out and the appropriate time to do so, the
StorTrends iTX stack utilizes a very efficient algorithm to perform the migration. The
Data Mover technology (that works by advertisement of blocks) ensures that data blocks
are migrated without corruption in the fastest possible time.
In essence, even at the block-level, efficient ILM is implemented by maintaining the
block-level metadata. No content analysis is attempted in managing blocks of data from
conception to extinction.
StorTrends iTX also migrates snapshots to a more cost-effective storage tier. Depending
on the access patterns, StorTrends iTX not only demotes inactive data to a less expensive
storage tier, but also compresses data at rest.
200 StorTrends® 1300 User's Guide (StorTrends iTX version 2.7)