Metrocluster with Continuous Access XP P9000 for Linux Version B.01.00.10 Release Notes

Support for Device Mapper
Metrocluster for Linux supports configuring Device Mapper for disks used in Metrocluster packages.
All the Serviceguard-related restrictions and guidelines for supporting DM-Multipath are also
applicable to Metrocluster configurations.
NOTE: Starting Serviceuard for Linux A.11.20.20, you can use Persistent Reservations with
Metrocluster for Linux when Device Mapper (DM) is enabled.
For more information on the restrictions, see HP Serviceguard for Linux Certification Matrix available
at http://www.hp.com/go/linux-serviceguard-docs.
Support for VMWare virtual machines as Metrocluster nodes
Metrocluster for Linux includes support for configuring VMWare virtual machines as Metrocluster
nodes. All Serviceguard related restrictions and guidelines for configuring VMWare virtual machines
as Serviceguard nodes are also applicable to Metrocluster configurations.
In Metrocluster configurations, Raw Device Mapping (RDM) is not supported. You must configure
the Fiber channel N-Port ID Virtualization (NPIV) for all the virtual machines. For more information
on configuring NPIV, see Using HP Serviceguard for Linux with VMWare virtual machines
whitepaper available at http://www.hp.com/go/linux-serviceguard-docs.
Serviceguard Cluster and Package Configuration Via Serviceguard
Manager or System Management Homepage
Starting with HP Serviceguard Manager B.03.31.10 available in Serviceguard A.11.20.10, the
following Serviceguard Manager operations are supported in a Metrocluster environment:
• Configuration, monitoring and administration of Metrocluster modular packages.
However, the following restriction applies:
• A Metrocluster package configuration requires a system administrator to configure data
replication, which is not supported by Serviceguard Manager. This step is required to be
performed by the administrator outside of the HP Serviceguard Manager.
For more information, see HP Serviceguard A.11.20.10 for Linux Release Notes available at
http://www.hp.com/go/linux-serviceguard-docs and HP Serviceguard Manager B.03.31.10
online help system that is available with the product.
Timing Considerations
The Metrocluster with Continuous Access XP P9000 for Linux gets the device status from the P9000
or XP series array and/or synchronize the device group during package startup. The time taken
by package startup depends upon the number of disk devices configured. Packages with many
disk devices will take longer to start up than those with fewer devices.
Some delay in the package startup time occurs in those situations where resynchronization of data
from one side to another is required. For example, if the Metrocluster package fails over to SVOL
side and if there is a Continuous Access link failure, it performs SVOL takeover (SSWS). After
Continuous Access link recovery, if the Metrocluster package fails back to PVOL side, it
resynchronizes the data from the SVOL side to the PVOL side.
For Continuous Access Journal mode package, journal volumes in PVOL may contain a significant
amount of journal data to be transferred to SVOL, the package startup time may increase significantly
when the package fails over and waits for all of the journal data to be flushed.
The value of run_script_timeout in the package ASCII file should be set to no_timeout or
to a large value. This value should be enough to take into consideration the extra startup time that
is attributed to getting the status from the P9000 series disk array. When using asynchronous data
replication, the value has to be 360 seconds or more.
Serviceguard Cluster and Package Configuration Via Serviceguard Manager or System Management Homepage 7