Veritas Volume Manager 5.0.1 Release Notes HP-UX 11i v3 (5900-0033, August 2011)

• DMP issues of Veritas Volume Manager
Following are the limitations of DMP:
◦ Handling intermittent failures in paths
The dmp_health_time and dmp_path_age tunables control how DMP handles
intermittently failing paths. The default values of dmp_health_time and dmp_path_age
are 60 and 300 seconds, respectively. The value of dmp_health_time represents the
minimum time in seconds for which a path must stay healthy. If a path changes state
between enabled and disabled on a shorter time scale than the dmp_health_time
value, DMP marks the path as intermittently failing and disables I/O on the path. I/O is
not re-enabled on an intermittently failing path until dmp_path_age seconds have elapsed
without further outage.
The minimum configurable value of dmp_path_age is 0, which prevents DMP from
detecting intermittently failing paths.
◦ Native rootability support limitation
Migration of a root disk from DMP to native multipathing or vice versa must be followed
by a system reboot. Online migration of native multipathing to DMP or vice versa is not
supported, that is, the changes will not be effective until the system reboots. VxVM also
disables the configuration daemon (vxconfigd) until the system reboots. This ensures
that any operation, which could lead to a configuration change, fails.
◦ Volume Manager commands take more time with HDS9500-ALUA arrays
Due to slow disk response time, Volume Manager commands take more time with
HDS9500-ALUA arrays. This issue only affects the HDS9500 configuration where some
vx commands may take longer to complete compared to VxVM 5.0 on the HP-UX 11i
v3 operating system. This is due to the slow disk response time and the change in default
behavior for device open caching. In VxVM 5.0, the device open caching was enabled
by default. In 5.0.1, device open caching is set to off. You can set the default behavior
by using the following command:
vxdctl cacheenable
You must disable the caching before making any dynamic configuration changes.
◦ Disk detach policy support in a campus cluster environment
In a campus cluster environment, the disk detach policy value for site consistent disk
groups must be set to Global. The value policy=local is not supported.
• No support for creating site-based snapshots.
• No Action pull-down menu items exist for the Layout View, the Disk View, or the Volume View
in VEA.
• A snapshot can be taken of a root volume, but the snapshot is not bootable. The data from
the snapshot would have to be restored to the original root volume before the machine can
be booted with the preserved data.
• Volume relayout is not supported for site-confined volumes or for site-consistent volumes in this
release.
• The vxvol command cannot be used to set site consistency on a volume unless sites and site
consistency have first been set up for the disk group.
• VxVM does not currently support RAID-5 volumes in cluster-shareable disk groups.
Known Problems And Workarounds
Following are the known limitations of VxVM 5.0.1 on HP-UX 11i v3:
16 Veritas Volume Manager 5.0.1 Release Notes