VERITAS Volume Manager 3.5 Migration Guide (September 2004)

Chapter 3

Command 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 command manual pages 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.