HP StorageWorks P9000 Virtualization Adapter Administrator Guide (5697-0680, October 2010)
Protection groups using Continuous Access Synchronous or Continuous Access
Synchronous CTG
If the disk pairs for a protection group are Continuous Access Synchronous, use a fence level of DATA.
If the fence level of NEVER is used, the internal horctakeover command fails (horctakeover returns
EX_VOLCUR). A fence level of NEVER cannot guarantee data consistency among all disks in a device
group when a single disk fails (because I/O is not fenced).
Virtual machines must be able to boot when a disaster occurs (failover), or when a failover test is
executed. When a disaster happens, it is acceptable to use fence level NEVER. Therefore, the P9000
Virtualization Adapter completes failover successfully, but horctakeover returns an EX_VOLCUR
error.
Fence level NEVER can be used under the following conditions:
• When using an application such as APP(SQL/Exchange/Oracle/..)
• The SRA does not swap from S-VOL to P-VOL when the Continuous Access link is active. Instead,
the failover succeeds and SRM is notified that all target volumes have changed to the S-VOL SSWS
state.
Protection groups and CT groups using XP Continuous Access Asynchronous
and Continuous Access Journal Software
If the P-VOLs for protection groups are CT group volumes using XP Continuous Access Asynchronous
or Continuous Access Journal Software, you must split all volumes (LUNs) associated with the protection
groups to ensure the P-VOLs of the protection groups are identical to the CT group.
MPIO (Multi Path I/O) Connection
In a Multi-Path I/O (MPIO) connection, SRM needs to discover both target port WWNs recognizing
an ESX Server in discovery phase. The P9000 Virtualization Adapter converts from a target port
number in horcm.conf to a target port WWN. Therefore, the P9000 Virtualization Adapter needs
to include the alternate path port and LUN number as shown Figure 9.
This example assumes that a target volume is connected to CL3-G and CL4-G for MPIO.
Figure 9 Multi Path I/O connection
.
Overview of the P9000 Virtualization Adapter18