HP P6000 Replication Solutions Manager Administrator Guide (T3680-96069, June 2012)

HP P6000 DC-Management VxVM requirements and considerations
• Shrink is not supported on VxVM volumes.
• Expand is supported on VxVM of CONCAT layout only. Grow is not supported on other
layouts, such as mirrored, striped, and layered.
• Online extend is supported on VxVM volumes with VxFS, provided that Online-JFS is also
available (no offline extend support).
• Extend is supported on VxVM volumes on HP-UX 11.23 and 11.31, with supported VxVM
versions for each operating system.
• HP P6000 DC-Management is enabled on VxVM volumes subject to VxVM restrictions (for
example, minimum disk layout Version 120; see VxVM documentation on Dynamic LUN
Expansion (DLE) for a complete list) and licensing requirements of DLE in VxVM.
• Cluster-aware VxVM volumes are not supported.
• VxVM volumes of type SPANNED (also called CONCAT) are supported for expansion.
Expansion is supported using two methods:
◦ Manual steps, using the Extend Capacity tab.
◦ Policy-based expansion, which is automatic and requires online volume expansion
capability by the host. There are two options:
– Weighted expansion (recommended). For a given expansion size, virtual disks (storage
volumes) constituting the VxVM volume are expanded, based on the size available
in their disk groups. The size of expanded individual virtual disks is proportional to
the space available in its array disk group. If virtual disks come from similar disk
groups, expansion occurs equally among storage volumes, to the closest integer
value.
– Equal expansion. For a given expansion size, underlying storage volumes constituting
VxVM volumes are expanded equally for a given expansion size of a VxVM volume.
Linux
This section describes special replication procedures for Linux hosts.
Adding device files on Linux hosts
By default, Red Hat Linux uses /dev/sg0 to /dev/sg31 for 32 SCSI devices. SUSE Linux uses
/dev/sg0 to /dev/sg15 for 16 SCSI devices. To discover all LUNs that are presented to a host,
the replication manager needs as many /dev/sg device files as there are SCSI devices. If
information is missing from the replication manager's host views, or if jobs fail at the
CreateHostVolume step, there may be an insufficient number of /dev/sg device files on the
Linux host.
Increase the number of device files by running the makesg.sh utility, which is provided with the
Linux host agent in the directory host_agent_install_directory/RSMHostSW/RSMHA
Follow these steps:
1. Determine the number of SCSI devices that the host sees by executing the following command
from the host's command line:
cat /proc/scsi/scsi
2. Count the number of attached devices.
3. Determine the number of /dev/sg device files by executing the following command:
ls /dev/sg*
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