Changelogs for new files to archive, applies policies to release files based on age or space usage, and communicates with MDT and Coordinator. The Policy Engine can also trigger actions like migration between, purge, and removal. The most commonly used policy engine is RobinHood, but other policy engines can also be used. HSM also defines new states for files including: Exist: Some copy, possibly incomplete exists in a HSM. Archive: A full copy exists on the archive side of the HSM. Dirty: The primary copy of the file has been modified and differs from the archived copy. Released: A stub inode exists on an MDT, but the data objects have been removed and the only copy exists in the archive. Lost: the archive copy of the file has been lost and cannot be restored No Release: the file should not be released from the filesystem No Archive: the file should not be archived Deployments Lustre is used by many of the TOP500 supercomputers and large multi-cluster sites. Six of the top 10 and more than 60 of the top 100 supercomputers use Lustre file systems. These include the 700TB 5GB/s Orion filesystem for the Frontier supercomputer at Oak Ridge National Laboratory (ORNL), Fugaku and K Computer at the RIKEN Advanced Institute for Computational Science, Tianhe-1A at the National Supercomputing Center in Tianjin, China, LUMI at CSC, Jaguar and Titan at ORNL, Blue Waters at the University of Illinois, and Sequoia and Blue Gene/L at Lawrence Livermore National Laboratory (LLNL). There are also large Lustre filesystems at the National Energy Research Scientific Computing Center, Pacific Northwest National Laboratory, Texas Advanced Computing Center, Brazilian National Laboratory of Scientific Computing, and NASA in North America, in Asia at Tokyo Institute of Technology, in Europe at CEA, and many others. Commercial technical support Commercial technical support for Lustre is often bundled along with the computing system or storage hardware sold by the vendor. Some vendors include Hewlett-Packard (as the HP StorageWorks Scalable File Share, circa 2004 through 2008), ATOS, Fujitsu. Vendors selling storage hardware with bundled Lustre support include Hitachi Data Systems (2012), DataDirect Networks (DDN), Aeon Computing, and others. It is also possible to get software-only support for Lustre file systems from some vendors, including Whamcloud. Amazon Web Services offers Amazon FSx for Lustre, a fully managed service, making it easy to launch and run high-performance file systems cost effectively in their cloud.