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

size, which increases the maximum snapshot capacity to an equivalent value, or delete any of the

snapshots that are not needed or in use.

• Warning: The pre-allocated extents could not be allocated for

space efficient snapshot "/dev/vg01/lvol1_S2".

Any future writes to successor of this snapshot logical

volume will mark this snapshot and all its predecessor

as inoperative.

During the volume group activation, vgchange reports that the pre-allocated extents cannot be

allocated for a space efficient snapshot because of the lack of free extents in the volume group

satisfying the snapshot allocation policy. This results in marking this snapshot and all its

predecessors as inoperative if any new writes are performed to its successor. This can occur when a

few of the physical volumes belonging to this volume group are unavailable during volume group

activation or when enough free physical extents are not available in the volume group. Add

physical volumes to the volume group using vgextend; make the unavailable physical volumes

available; or for mirrored space-efficient snapshots, if this error occurred because of the strictness

policy of mirroring, you might consider choosing a lesser strictness policy for the snapshot. Then,

deactivate and activate the volume group before using the space efficient snapshot or its successor.

• Warning: The space efficient snapshot "/dev/vg01/lvol1_S2"

has been marked as read-only.

During the volume group activation, vgchange reports that the space-efficient snapshot has been

marked as read-only. This can happen when the pre-allocated extents cannot be allocated for the

space efficient snapshot during volume group activation. This warning is displayed after the

previous warning message. After the previous warning is handled, you will no longer see

this warning.

• Warning: Deletion of a snapshot can result in its unshared data being

copied to its predecessor. If the predecessor is a space-efficient

snapshot, ensure that it has sufficient number of pre-allocated extents

so that the data unsharing doesn't result in the predecessor being

marked as inoperative.

When a single snapshot logical volume is deleted, if the snapshot has a predecessor that is not

marked over-commit or inoperative, for all unshare units of the predecessor that share data with this

snapshot, only the unshared data of the snapshot is copied to the predecessor. If the predecessor is

a space-efficient snapshot that contains useful information, ensure that sufficient number of extents

are pre-allocated to prevent it from being marked over-commit due the unshare data copy during

snapshot deletion. Using the lvdisplay on the snapshot being deleted, you can determine the

maximum number of extents that are required on the predecessor.

• LVM: WARNING: Snapshot LV (VG 128 0x000000, LV Number: 6) threshold

value reached. Please increase the number of pre-allocated extents for

this snapshot LV

This message in the syslog reports that the particular space efficient snapshot has reached its

threshold number of pre-allocated extents. This can occur when writes happening on either the

space-efficient snapshot or its successor logical volume on the snapshot tree has used up most of the

extents in the pre-allocated extent pool. Increase the number of pre-allocated extents for this space-

efficient snapshot to prevent it from becoming in-operative.

• Error: The specified logical volume "/dev/vg01/lvol1_S2" is

inoperative.

pvmove cannot be performed on logical volumes that are inoperative.