A Troubleshooting; Vls Common Issues - HP 12000 User Manual

A Troubleshooting

This appendix describes some common issues you may encounter while configuring or using the
VLS including automigration/replication and deduplication issues.

VLS Common Issues

Symptom
Some of the virtual devices are not
detected by the operating system
when it scans the SAN for new
hardware.
The virtual tape drive devices either
disappear or move to a different
Possible causes
There are more LUNs on the FC host
ports than the operating system is
configured to see. Once the maximum
number of LUNs on a device is
detected, the operating system stops
looking for more LUNs. In the case of
the VLS, the operating system
considers each FC host port to be one
device. So, if the maximum number of
LUNs an operating system is
configured to see is eight, the
operating system will only see LUN0,
LUN1, ..., LUN7 and will not see
LUN8, LUN9, ..., and up on each FC
host port. By default Windows and
HP-UX hosts can see a maximum of 8
LUNs per FC host port.
There is a gap in the LUN numbering
on the FC host port. Most operating
systems will stop looking for virtual
devices on an FC host port once a
gap in the LUN numbering is detected.
For example, if LUN0, LUN1, and
LUN3 are mapped to an FC host port,
the operating system will see LUN0
and LUN1. When it does not find a
LUN2, it will assume there are no
more LUNs on the port and stop
looking.
There are two levels of logical device
binding in the Windows OS. At the
Solution
Increase the maximum number of LUNs
per device the operating system is
configured to see. To change the
maximum LUN per device setting:
For Microsoft Windows—See
http://support.microsoft.com/
default.aspx?
scid=kb%3ben-us%3b310072.
For HP-UX—The value can only be
changed for HP-UX versions 1 1.31
and later. Increase the number of
LUNs per bus on the HP-UX server
by entering # scsimgr set_attr
-a max_lunid=32. You can view
the connected IO by entering #
ioscan -m lun.
You cannot create legacy DSFs for
LUN IDs above 7; use persistent
device special files instead.
See the HP-UX documentation for
more information.
For other operating systems—See
the operating system web site.
Use the VLS's LUN masking feature to
restrict the number of virtual devices the
host sees on the VLS FC host ports, so
it only sees the virtual devices it needs
to see. Then, use the VLS's LUN
mapping feature to assign LUNs to the
virtual devices the host can see, such
that the virtual device LUN numbers
include a LUN0 and no gaps in the
LUN numbering. See LUN Masking
LUN Mapping for instructions.
Remove the gap in the LUN numbering
by editing the host's LUN mapping (see
LUN Mapping), or if a virtual device
has been destroyed on the VLS,
creating a gap in the LUN numbering,
restart the VLS device emulations. The
VLS firmware will reassign LUNs to the
virtual devices as necessary to remove
any gaps in the LUN numbering. See
Restarting VLS Device Emulations.
Delete the Windows NtmsData
database and put the RSM into the
Disabled state using the following
procedure :
VLS Common Issues 173
and