Persistent Storage Management Elements; Snapshot Facts - HP StorageWorks NAS e7000 V2 Quick Start Manual

Persistent Storage Management Elements

Persistent Storage Manager lets the administrator make persistent images, also
known as snapshots. Snapshots enable the creation of multipurpose logical
replicas of production data without having to physically copy the data. They can
be used to immediately recover a lost file or directory, to test a new application
with realistic data without affecting the "real" data, and to serve as a source of
data for backups. Snapshots are a temporary representation of the data and are not
meant to be permanent.
Snapshots use existing space from the volume, partition, or logical drive to
maintain the data required to present the original data. This space is termed the
cache file. By default the cache files consumes 10 percent of the available space of
a logical storage element. Snapshots can be read only, read-write or always keep.
If snapshots are shared, users can access a snapshot and edit the data.
Write-enabled snapshots may be reverted to their original dataset by altering the
snapshot type back to read only.

Snapshot Facts

Full documentation of Persistent Storage Manager may be found in the
administration guide.
NAS e7000 v2 Quick Start Guide
Snapshots are created on a per volume, volume group, partition, or logical
drive basis.
Snapshots can be read-only, read-write or always keep.
Snapshots are mounted as a mount point on the root of the volume, partition
or logical drive.
Snapshots can be shared in the same manner as any other folder, drive or
mount point.
Snapshots are meant to be temporary in nature.
Snapshots are automatically deleted if disk space becomes critical and they
are not set to always keep.
Persistent Storage Manager only writes to the cache file on the first change of
the underlying data.
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