HP StorageWorks XP24000 for FlashCopy Mirroring Software User's Guide (T5240-96001, June 2007)

2 About Version 1 Operations

This chapter provides an overview of Version 1 o perations.

How Version 1 Works

Version 1 prov

ides a fast data replication capability. Version 1 allows you to create a copy of an S-VOL

on a

T-VOL virtually or physically. A volume pair created by Version 1 is called a relationship. Once

this

relationship is established, the T-VOL (the virtual or physical copy of the S-VOL) is available for

both

read and w

rite operations.

When you establish a Version 1 relationship, you can specify a range of data to be copied, which is

called

an extent. Version 1 allows you to specify one copy target extent p er copy sourc e extent.

Establishing a Version 1 Relationship

You specify ShadowImage for Mainframe volumes for the copy source or copy target of a Version 1

relationship. However, you cannot establish a Version 1 relationship if the desired S-VOL has already

three T-VOLs.

There are two kinds of copying processes for Version 1: background and on-demand. Background

copying copies all data within the copy range that is speciﬁed when you establish the relationship.

On-demand copying copies data when a read or write request occurs for an area that is not copied

yet. In this case, the area will be copied before the request is actually executed. For details, see

“Copy Modes”onpage43.

If you do not specify any additional p arameter, when the background copy of the extent data is

completed, the relationship ends automatically. If you do not want to release the relationship after the

copy operation completes, you need to establish the relationship in NO COPY mode. For details, see

“Establishing a Version 1 Relationship” on page 33.

Releasing a V ersion 1 Relationship

Normally, a Version 1 relationship will be released automatically when the background copy of the

extent data is completed. However, if you specify NOCOPY for the copy mode when you establish a

relatio

nship, the relationship will be maintained even when the copying processing completes.

You need to issue the FCWITHDR command to release a Version 1 relationship whose background copy

of the extent data is not yet completed, or to release a relationship which was established with the

NOCOPY mode. For details, see “Releasing a V ersion 1 Relationship Using FCWITHDR” on page 37.

Status of a Relationship

Figure 1 on page 16 illustrates the pair status transition and the relationship between the relationship

status and the Version 1 operations.

XP24000 for FlashCopy Mirroring Software User's Guide