HP StorageWorks XP Remote Web Console Software - Manual (Page 13)

Snapshot XP user guide 13
Business Copy XP
Use Business Copy XP to maintain disk array-internal copies of all user data on the XP10000/XP12000
for data on open systems such as UNIX and PC servers. Business Copy XP creates a pair of P-VOL and
S-VOL, both of which are logical volumes in the same disk array. Pairs that Business Copy XP creates are
called Business Copy XP pairs.
RAID-protected S-VOLs are created within the same XP10000/XP12000 as the P-VOL. Use Business Copy
XP to create up to three S-VOLs for a P-VOL. Using Business Copy XP with External Storage XP, you can use
external volumes to create Business Copy XP pairs.
Unlike the Snapshot XP pair’s S-VOL, all P-VOL data is copied to the Business Copy XP pair’s S-VOL.
Therefore, the capacity of the Business Copy XP pair’s P-VOL and S-VOL is the same. In addition, Business
Copy XP’s copy process takes longer because all P-VOL data is copied to the S-VOL.
As described previously, Business Copy XP requires larger disk array capacity and the copy process takes
longer compared to Snapshot XP. However, when a failure disables access to one of the pair’s volumes,
the disk array can continue to operate using data stored in the other volume because the same data is
stored in the P-VOL and S-VOL. HP recommends that you use Business Copy XP when data integrity is more
important than copy process speed or disk array capacity. For more information, see the HP StorageWorks
Business Copy XP User Guide for the XP10000/XP12000.
Snapshot XP functions
Snapshot XP creates pairs consisting of a P-VOL and S-VOL. When creating a pair, Snapshot XP uses a
V-VOL as the pair’s S-VOL. In addition, you can manage the P-VOL’s snapshot data by copying the data to
an area called the pool. This section describes the volumes Snapshot XP uses first, and then describes
Snapshot XP functions.
Volumes Snapshot XP uses
Snapshot XP uses the P-VOL, S-VOL, and pool-VOL. This section describes the requirements (such as
emulation type or path definition) for the volumes Snapshot XP uses.
Snapshot XP primary volumes
Table 1 Requirements for Snapshot XP P-VOLs
Item Requirement
Volume type Logical volume (LDEV)
LUSE volume can be specified.
NOTE: A LUSE P-VOL must be paired with an S-VOL that has the same size and structure.
For example, if a LUSE P-VOL is created by combining volumes that have 1 GB, 2 GB, and
3 GB in that order, you must specify a LUSE volume that has exactly the same size and
combination order as the S-VOL.
You cannot specify the following volumes as Snapshot XP P-VOLs:
• Volumes used as pool-VOLs
• Volumes used as a Snapshot XP pair’s S-VOL
• Volumes used by another software product’s pair or migration plan, except Continuous
Access XP and Continuous Access XP Journal
• NAS volumes
Emulation type OPEN-V
Maximum number 8,191
For more information about the maximum number of Snapshot XP pairs that can be created,
see ” Calculating the number of Snapshot XP pairs that can be created ” on page 19.