HP XP P9500 Storage - Manual (Page 20)

Planning volume pairs
To plan Continuous Access Synchronous pair volumes, you need to do the following:
•
At the local site, identify the volumes that contain important data to be backed up.
•
At the remote site, set up the volumes that will hold the copied data.
Volume pair requirements and recommendations
The following requirements and information are provided to help you prepare Continuous Access
Synchronous volumes:
•
A volume can only be assigned to one Continuous Access Synchronous pair.
•
The S-VOL must be the same size as the P-VOL.
•
Continuous Access Synchronous requires a one-to-one relationship between the P-VOL and
S-VOL. The P-VOL cannot be copied to more than one S-VOL, and more than one P-VOL cannot
be copied to one S-VOL.
•
Logical Volume Images (LVIs)
•
Logical Unit (LU) Types
Continuous Access Synchronous supports the basic LU types that can be configured on
the P9500 (for example, OPEN-3, OPEN-E, OPEN-8, OPEN-9, OPEN-L, OPEN-V). ◦
◦ Continuous Access Synchronous pair volumes must consist of LUs of the same type and
capacity (for example, OPEN-3 to OPEN-3). The P-VOL and S-VOL LU types are displayed
in Remote Web Console.
◦ Multiplatform volumes (for example, 3390 3A/B/C) cannot be assigned to Continuous
Access Synchronous pairs. Contact your HP account team for the latest information on
supported devices for your platform.
•
Continuous Access Synchronous operates on volumes rather than on files; multivolume datasets
files require special attention. For complete duplication and recovery of a multivolume files
(for example, a large database file that spans several volumes), make sure that all volumes
of the file are copied to Continuous Access Synchronous S-VOL.
•
Continuous Access Synchronous pair volumes can be shared with non-Continuous Access
Synchronous program products. See
“Sharing Continuous Access Synchronous volumes”
(page 31) for more information.
•
Continuous Access Synchronous supports LUN Expansion (LUSE). This allows you to configure
expanded LUs using two or more contiguous LDEVs (up to 36).
◦ If two LUSE volumes are paired with Continuous Access Synchronous, a LUSE P-VOL must
be paired with an S-VOL of the same size and structure. For example, if a LUSE P-VOL is
connected with volumes of 1GB, 2GB, and 3GB in this order, you must specify a LUSE
volume that has exactly the same size and the same connection order as the S-VOL.
◦ The number of LDEV pairs in a Continuous Access Synchronous LUSE pair equals the
number of LDEVs in each LUSE volume.
◦ When the status of all LDEV pairs within one Continuous Access Synchronous LUSE pair
is not the same (for example, one LDEV pair is suspended), the pair status of the Continuous
Access Synchronous LUSE pair changes to PDUB.
•
Continuous Access Synchronous also supports Custom volume sizes. This allows you to configure
LUs that are smaller than standard LUs. When custom-size LUs are assigned to a Continuous
Access Synchronous pair, the S-VOL must have the same capacity as the P-VOL. Remote Web
Console displays the size of the P-VOLs and S-VOLs.
20 Planning for Continuous Access Synchronous