About Thin Image - Hitachi VSP G1000 User Manual

About Thin Image

Hitachi Thin Image stores snapshots in a Hitachi Virtual Storage Platform
family (VSP family) storage system. If the data of the storage system fails,
you can restore it using the stored snapshot of the data. Pairs created by
using Thin Image are called Thin Image pairs in this document.
To store snapshot data, you create a pair with a logical volume functioning as
the P-VOL, and a virtual volume as the S-VOL. A pair created to store
snapshot data is referred to as a snapshot pair. A snapshot pair displays
showing the snapshot attribute.
When you create a Thin Image pair, the status changes to "PAIR" and
snapshot data is stored. You can use Thin Image to store a maximum of
1,024 snapshots of data (including the number of clones when you clone a
volume).
Updating the P-VOL first copies the differential data as snapshot data in pool
volumes (pool-VOL), and then updates the data. Snapshot data is a copy of
differential data in Thin Image P-VOLs. If your storage system experiences a
data storage failure, you can restore the data using the snapshot data in the
pool.
Splitting a Thin Image pair saves a snapshot and stops the copying of
replaced data in the pool.
The following figure provides a basic illustration of storing snapshot data.
16 Overview of Thin Image
Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series