Considering The P-Vol Fence-Level Setting; Fence-Level Settings On Continuous Access Xp Sync P-Vols - HP xp12000 User Manual

1. Identify volumes and volume groups containing important files and data for disaster recovery. In
addition to supporting Continuous Access XP remote copy operations as well as RAID Manager
commands, the disk array provides battery-backed nonvolatile duplexed cache, full hardware
redundancy, dynamic sparing, and an advanced RAID-5 implementation to ensure full data integrity if
a sudden power outage or other failure occurs.
2. Install Continuous Access XP. Install the Command View XP management station or use XP Remote Web
Console to establish Continuous Access XP operations for volumes and groups identified in
Select the proper CU images to access the volumes. See
operations" on page 31 for instructions on installing Continuous Access XP. See
Continuous Access XP configuration
Access XP configuration operations. See
page 89 for instructions on performing Continuous Access XP pair operations.
3. Use the appropriate combination of Continuous Access XP options for disaster recovery:
• Continuous Access XP Async offloading timer option (see
and copy pending timeout group option (see
Option)" on page 80). Use the copy pending timeout group option to limit the time duration during
which updates may be lost.
NOTE:
timer to 35 seconds or less to avoid affecting host I/O performance.
• Continuous Access XP Async Error Level pair option and Continuous Access XP Synchronous P-VOL
Fence Level pair option (see
page 93).
4. Establish file and database recovery procedures. These procedures should already be established for
recovering volumes that become inaccessible due to control unit failure.
5. Ensure that the host system at the primary site is configured to receive sense information from MCUs
(via RAID Manager or SNMP).
6. Install and configure host failover software between the main and remote sites. Host failover capability
is essential if you use the P-VOL fence-level setting of S-VOL Status or Never for any Continuous Access
XP volume pairs.

Considering the P-VOL fence-level setting

The P-VOL fence-level setting (see
for each Continuous Access XP Synchronous volume pair determines whether the P-VOL is fenced when
Continuous Access XP remote copy operations fail. Table 27 summarizes the effect of the fence-level setting
on a Continuous Access XP Sync P-VOL.
NOTE: The P-VOL fence-level setting does not apply to Continuous Access XP Asynchronous pairs.
Continuous Access XP Async P-VOLs are never fenced due to suspension of the pair.
Table 27

Fence-level settings on Continuous Access XP Sync P-VOLs

Type of failure
Update copy operation failed,
and the MCU changed the
status of the S-VOL to PSUE.
Update copy operation failed,
and the MCU could NOT
change the status of the S-VOL
to PSUE.
When channel extenders are used for Continuous Access XP Async, set the offloading
"Creating Continuous Access XP volume pairs
"Creating Continuous Access XP volume pairs
Write I/O operations to the
P-VOL will be:
Write I/O operations to the
P-VOL will be:
"Preparing for Continuous Access XP
operations" on page 62 for instructions on performing Continuous
"Performing Continuous Access XP pair
"Modifying consistency group options (CT Group
Fence-level setting
S-VOL Data
REJECTED
REJECTED
Continuous Access XP user guide for the XP12000/XP10000 109
"Performing
operations" on
"Asynchronous copy option" on page 82)
(Paircreate)" on
(Paircreate)" on page 93)
S-VOL Status
Accepted
REJECTED
step 1.
Never
Accepted
Accepted