Hierarchical Storage Management
• Automatically migrate data according to frequency of
user access and age:
– Increases the effective “value” of storage resources
– Designed for automatic archiving (backup/recovery)
– Not a new technology
Online
Nearline
storage
storage
Archival
storage
Hierarchical Storage Management (HSM) tools automate the migration of data
from one storage class to another based on how old the data is and how
frequently users access it.
Based on these criteria, the HSM application automatically migrates storage
from online storage to nearline storage or to offline or archival storage. It can
also migrate data back from nearline storage when a user requests the data.
HSM applications were designed primarily to automate the process of
archiving data.
HSM applications leave a “stub” when a file is removed from the online file
system. When the user application attempts to access the stub, the HSM
application is automatically notified and begins the process of retrieving the
data from nearline storage. This may or may not be a transparent process to
the user.