HP-UX 11i v3 Using LVM Logical Volume Snapshots (September 2010)

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The status of the logical volume specifies the type of snapshot logical volume (space-efficient or fully-
allocated). In this example, both the snapshots are operative. For the space-efficient snapshot, the
pre-allocated LE shows the total number of extents set aside for unsharing (50) and Unshared LE
shows the number of unshared extents (2). The difference between these two values is the number of
extents currently available for unsharing in the pre-allocated pool. This value is shown in
Current pre-allocated LE as 48. The space-efficient snapshot has one mirror copy, so the
Current pre-allocated PE shows the number of physical extents in the pre-allocated pool for all
mirror copies of the snapshot logical volume. For the fully-allocated snapshot, the Unshared LE is 0,
implying that it shares all its data with its successor.
# vgdisplay -v vg01
--- Volume groups ---
VG Name /dev/vg01
VG Write Access read/write
VG Status available
Max LV 2047
Cur LV 3
Open LV 3
Cur Snapshot LV 2
Max PV 2048
Cur PV 2
Act PV 2
Max PE per PV 2097152
VGDA 4
PE Size (Mbytes) 8
Unshare unit size (Kbytes) 2048
Total PE 5048
Alloc PE 356
Current pre-allocated PE 96
Free PE 4692
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0
VG Version 2.2
VG Max Size 128t
VG Max Extents 16777216
Cur Snapshot Capacity 2g
Max Snapshot Capacity 128t
--- Logical volumes ---
LV Name /dev/vg01/lvol1
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 128
Allocated PE 128
Used PV 1
--- Snapshot logical volumes ---
LV Name /dev/vg01/lvol1_S2
LV Status available/syncd, snapshot,space efficient
Snapshot Status operative
LV Size (Mbytes) 1024
Current LE 128
Allocated PE 4
Pre-allocated LE 50
Current pre-allocated LE 48
Unshared LE 2
Current pre-allocated PE 96
Used PV 2