HP-UX Reference (11i v2 07/12) - 1M System Administration Commands A-M (vol 3)

lvcreate(1M) lvcreate(1M)

The following command creates a logical volume in vgtest with EXTENT-BASED MIRRORED STRIPES:

lvcreate -D y -s g -m 1 -l 5 /dev/vgtest

The distributed allocation proceeds as follows:

• A free extent is allocated from the 1st pvol in pvg1.

• A free extent is allocated from the 2nd pvol in pvg1.

• A free extent is allocated from the 1st pvol in pvg1.

• A free extent is allocated from the 2nd pvol in pvg1.

• A free extent is allocated from the 1st pvol in pvg1.

• Mirrors for the ﬁve extents are then allocated from the free extents in pvg2 in a similar manner.

WARNINGS

The root, swap, and dump logical volumes (see lvlnboot(1M)) must be created with contiguous allocation

policy.

By setting mirror consistency recovery off, crash recovery time will be reduced. After a system crash the

mirrored logical volume will be available, but there may not be consistent data across each mirror copy.

The only types of data that can safely be put on a mirrored logical volume with mirror consistency recovery

turned off are:

• data not needed after a crash, such as swap or other raw scratch data, or

• data that an application itself will automatically reconstruct; for example, a raw logical volume for

which a database keeps a log of incomplete transactions.

In order to create a logical volume greater than 2 terabytes, the kernel must be updated to support this

feature, and the corresponding feature enabling patch must be installed.

In order to create a striped and mirrored logical volume, the kernel must be updated to support this

feature, and the corresponding feature enabling patch must be installed.

The creation of striped and mirrored logical volume(s) may prevent the import and activation of the volume

group on an earlier HP-UX release. See lvcreate(1M) on the earlier release to see if it explicitly states that

striping and mirroring is supported. If the striped and mirrored logical volumes of the volume group are

removed or un-mirrored, the volume group becomes again compatible with the older HP-UX releases.