VERITAS Volume Manager 3.1 Migration Guide

Converting LVM to VxVM
General Information Regarding Conversion Speed
Chapter 258
examples:
all:Rollback all converted LVM Volume Groups
listvg:list all LVM Volume Groups eligible for rollback
list:list all disk devices
vg_name:a single LVM Volume Group, named vg_name
<pattern>:for example vg08 vg09 vg05
Select Volume Group(s) to rollback :
[<pattern-list>,all,list,listvg,q,?]
vg08
Roll back this Volume Group? [y,n,q,?] (default: y)
Rolling back LVM configuration records for Volume Group
vg08
Selected Volume Groups have been restored.
Hit RETURN to continue.
Rollback other LVM Volume Groups? [y,n,q,?] (default: n)
General Information Regarding Conversion
Speed
The speed of the process of converting an existing LVM volume group to
a similar VxVM disk group is largely dependent upon the size of the
volume group being converted, as well as on the complexity of the
volumes within that volume group.
Factors affecting conversion speed include:
• size of volume groups. The larger the volume groups, the larger the
area for LVM metadata on each disk. A copy must be made of the
LVM metadata for each physical disk. Some areas are greater than
2MB; therefore, a 50-disk volume group requires 50 2MB reads and
writes (i.e., 100 large I/Os) to complete.
• individual size of a logical volume in a volume group, and the
complexity of the logical volume layout. For example, for a system
with 50 9GB drives, a simple 50GB logical volume of the first 5 1/2
disks can be created. But a 50GB striped logical volume that takes
the first 1GB of all 50 disks can also be created. The first and simple
logical volume takes less time to convert than the striped volume;
since only 5 disks need to be checked for metadata, only 5 disks must