HP StorageWorks XP Remote Web Console Software - Manual (Page 62)

62 Continuous Access XP Journal
As explained previously, when the host in the primary site issues an I/O request to the Continuous Access
XP (synchronous) P-VOL, data is restored asynchronously to the Continuous Access XP Journal secondary
data volume in the secondary site in a remote location.
Figure 28 Basic behavior in 3DC cascading configuration
If a Continuous Access XP (synchronous) pair is suspended in a 3DC cascading configuration, you can
resynchronize the pair using a differential copy. If a Continuous Access XP Journal pair is suspended, you
can resynchronize the pair using a differential copy.
NOTE: To perform disaster recovery from a failure in the primary site in a 3DC cascading configuration,
ensure that the fence level of the Continuous Access XP (synchronous) P-VOL is Data. If this fence level is
specified, you can perform disaster recovery using the Continuous Access XP Journal secondary data
volume containing data stored in the Continuous Access XP (synchronous) P-VOL.
Hardware configuration
This section explains the hardware configuration for a 3DC cascading configuration using Continuous
Access XP (synchronous) and Continuous Access XP Journal. In a 3DC cascading configuration, three disk
arrays are required. HP recommends that you install RAID Manager on hosts in the primary, intermediate,
and secondary sites. For Command View XP, a management station is required for these sites. The
following explains hardware configuration for these sites.
• Local disk array at the primary site
• Continuous Access XP (synchronous) must be installed.
• Must have a Continuous Access XP (synchronous) P-VOL.
• Local disk array at the Intermediate site
• Continuous Access XP (synchronous) must be installed.
• Continuous Access XP Journal must be installed.
• Must have a volume used as a Continuous Access XP (synchronous) S-VOL and a Continuous Access
XP Journal primary data volume.
• Must have a Continuous Access XP Journal master journal volume.
• Local disk array at the remote site
• Continuous Access XP Journal must be installed.
• Must have a Continuous Access XP Journal secondary data volume.
• Must have a Continuous Access XP Journal restore journal volume.
Setup procedure
This section explains the procedure for setting up a 3DC cascading configuration using Continuous Access
XP (synchronous) and Continuous Access XP Journal.
1. Install Continuous Access XP (synchronous) and Continuous Access XP Journal. Configure ports and
journal groups.
2. Issue a request for creating a Continuous Access XP (synchronous) pair to the primary disk array where
Continuous Access XP (synchronous) is installed.
3. Wait until the status of the Continuous Access XP (synchronous) pair becomes PAIR.