Hitachi VSP G400 User Guide

Item Thin Image (HTI) ShadowImage (SI)
differential data of the P-VOL is
retained.
1
Impact on P-VOL performance
when accessing backed up
data.
P-VOL performance is affected
because data in the P-VOL is
shared.
2
P-VOL performance is not
affected because the P-VOL and
the S-VOL can be disconnected.
Notes:
1. For snapshot pairs. When a cloned pair is created, all data in the P-VOL is retained and more
capacity is required for backup.
2. For snapshot pairs. When a cloned pair is created, the P-VOL and the S-VOL can be separated
and the P-VOL performance is not affected.
Recommended usage
To maintain backed up data for long periods, save it on magnetic tapes or
other media. For temporary backups use HTI or SI. When backing up data to
magnetic tapes use SI. To reduce the capacity necessary for backups use
HTI, but note that this affects P-VOL performance.
Use SI to minimize the impact from P-VOL physical failures. If you need four
or more generations of backups, use both SI and HTI as shown in the
following figure.
Thin Image system and planning requirements 97
Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series

Hitachi VSP G400 Specifications

General

Brand	Hitachi
Model	VSP G400
Category	Storage
Language	English