HP-UX vPars and Integrity VM V6.3 Administrator Guide

Figure 8 Sub-LUN storage allocation example
Whole Disk
Logical Volume Logical Volume Logical Volume Logical Volume
File File File File File File File File
2
2 2
1
The VM is allocated a logical volume from the LUN for a Virtual LvDisk.
• The logical volume that has been allocated is labeled 1.
• The parts of the disk that cannot be allocated are labeled 2.
Those parts that are no longer available include the files that were on the logical volume and the
whole disk that makes up part of the volume group. If any of these parts are allocated for other
virtual devices, data on the Virtual LvDisk can get unintentionally over-written.
Those parts that are still available for reallocation include other logical volumes that are on the
disk, and files that are on those logical volumes. These pieces can be allocated without the problem
of data getting damaged because they do not overlap with the Virtual LvDisk.
You must avoid whole LUN collisions, beyond avoiding sub-LUN collisions. The same storage
resource, virtual, or attached, cannot be specified more than once to the same VM. HP-UX 11i v3
supports both legacy per-path device files (for example, /dev/rdsk/c6t2d0) and agile non-path
specific device files (for example, /dev/rdisk/disk). As shown in Figure 9 (page 71), there
may be more than one legacy device file that points to the same physical storage device, while
there is only one agile device file for a given physical storage device. Starting vPar and Integrity
VM V6.0 onwards, only agile DSFs must be used to configure guest backing stores. Adding virtual
devices to the guest using legacy device files or starting a guest that contains backing stores
specified using legacy files will fail.
70 Storage devices