HP StorageWorks XP Remote Web Console Software - Manual (Page 9)

1 Overview of HP StorageWorks
XP Snapshot
The HP storage system provides various copy solutions (program products) such as HP StorageWorks XP
Continuous Access Software and HP StorageWorks XP External Storage Software. Among these solutions,
this chapter provides an overview of XP Snapshot and HP StorageWorks XP Business Copy Software,
which is a prerequisite program product of XP Snapshot.
Note : The use of XP Snapshot, Business Copy, and all other storage system products is governed by
the terms of your license agreement(s) with HP.
Overview of XP Snapshot
XP Snapshot is a program product which enables you to maintain and copy all data on the storage
system. XP Snapshot is used for data for open systems such as UNIX and PC servers. XP Snapshot creates
pairs of a primary volume and a secondary volume. Primary volumes (hereinafter referred to as P-VOLs)
are logical volumes, and secondary volumes (hereinafter referred to as S-VOLs) are virtual volumes
(hereinafter referred to as V-VOLs). The pair created by XP Snapshot is called an XP Snapshot pair in this
document. In addition, the use of XP Snapshot involves Business Copy.
Figure 1 on page 9 illustrates the mechanism to copy the data in the storage system using XP Snapshot.
Figure 1 The Mechanism of XP Snapshot
In the figure above, Data A is stored in some part of the P-VOL of an XP Snapshot pair. When the
host requests to update Data A to Data B, XP Snapshot will copy Data A copied to the pool volume
(hereinafter referred to as pool-VOL) in the pool before the P-VOL is updated. After the copy operation of
XP24000 Snapshot User's Guide 9