VERITAS Volume Manager 5.0 Migration Guide (September 2006)

65Command differences

Existing Features in LVM not supported in VxVM

Some of the existing features in LVM are not supported in the current release of VxVM.

Given below is a table with the unsupported LVM features, and possible workarounds in

VxVM.

Table 3-4 LVM features and VxVM equivalents

LVM Feature VxVM Equivalent

Physical volume groups VxVM has no equivalent feature. The disk group

feature of VxVM combines the logical volume

group (VG) and physical volume group (PVG)

of LVM.

Powerfail timeout feature: Automatically re-

enable a disk or a path to a disk, after temporary

error condition (resulting in

EPOWERF error on I/Os) disappears on that

disk or path.

Powerfail timeout feature: After the EPOWERF

error condition disappears, the reconfiguration

command must be run manually to re-enable the

paths and the disks which were disabled due to

EPOWERF error. See the pfto feature in the

vxdctl(1M) manual page for more

information.

Logical Volume Timeout (LVTO). If LVTO on a

logical volume is set to zero, which is the

default, an I/O is retried forever.

VxVM does not support the LVTO feature.

However, VxVM supports the powerfail timeout

feature to handle transient error conditions.

VxVM tries an I/O only on active paths to a

disk; hence, it never retries indefinitely. See the

powerfail timeout feature and also refer to the

pfto feature in the vxpfto manual pages for

more details.

Bad media block relocation. VxVM relocates whole subdisks. Smaller

granularity relocation is not supported. The bad

block reallocation feature does not exist in

VxVM because the vectoring of bad blocks is

now done by most hardware.