HP XP20000XP24000 Disk Array - Manual (Page 13)

Note 1: The number of expanded LUs (LDEVs) should not exceed 36, even if the LUSE volume contains
another LUSE volume.
Note 2: Combining RAID 1 and RAID 5 volumes into the same LUSE volume is supported, but not
recommended.
Note 3: If you combine LDEV00, LDEV03, and LDEV05 into LUSE 1, LDEV02 and LDEV04 into LUSE 2,
and LDEV06 and LDEV07 into LUSE3, you can also combine LUSE 1 and LUSE 3. However, you cannot
combine LUSE 1 and LUSE 2 because the LDEV range in LUSE 1 and LUSE 2 overlaps.
Note 4: A LUSE volume contains up to 4 MB of disk area to be used for controlling the volume, and
this disk area cannot contain user data. Therefore, the maximum capacity for user data in a LUSE
volume is less than 60 TB.
Table 3 Specifications and Restrictions on LDEVs Released from a LUSE Volume
No. Specifications and Restrictions
1 The LUSE volume must not have any defined path.
2 The access attribute must be set to Read/Write.
LUSE Operations Using a Path-defined LDEV
When you create a LUSE volume, the top LUSE volume can be either an LDEV or a LUSE volume that has
one or more paths defined to it. Only the top volume in the LUSE volume to be created can have any
paths. The other volumes in the LUSE volume to be created must not have any paths.
Note : You can perform a LUSE operation using a path-defined LDEV regardless of how many paths
are defined to the LDEV.
Note : You cannot combine a path-defined LDEV or LUSE volume with another path-defined LDEV
or LUSE volume.
Note : When you start the LUSE operation to combine a path-defined LDEV or LUSE volume with another
path-defined LDEV or LUSE volume, a dialog box will appear with a message asking if you want to
continue the operation. Click the OK button if you want to continue or the Cancel button if you do not.
Note the following points when you perform a LUSE operation using a path-defined LDEV:
• Caution : If a path is defined from a Windows 2000 host, a Windows Server 2003 host, or an
AIX5.2 host to an LDEV, the LDEV can be used for LUSE operations using a path-defined LDEV.
However, if a path is defined from a host running another operating system to an LDEV, the LDEV
cannot be used for LUSE operations using a path-defined LDEV.
• Caution : If a path is defined from a Windows 2000 host or a Windows Server 2003 host to an
LDEV and you want to perform a LUSE operation that handles this path-defined LDEV, you must
ensure that the host mode for the Windows host is 2C (Windows Extension). If the host mode is
not 2C, you must change the host mode to 2C before performing the LUSE operation.
XP24000 LUN Expansion User's Guide 13