AIX Version 4.3 Differences Guide

It provides a fast version of importvg that checks the Volume Group Descriptor
Areas (VGDA) of only the disks that are members of the designated volume
group. As a result, if a user exercises this flag, they must ensure that all physical
volumes in the volume group are in a good and known state. If this flag is used on
a volume group where a disk may be in missing or removed state, the command
may fail, or the results may be inconsistent. This flag has the advantage of
avoiding a lengthy search for missing disks that happens during normal importvg
processing. Administration of large SSA disk arrays will greatly benefit from the
terse search the -F option provides.
5.4 Raw LV Online Mirror Backup Support (4.3.1)
The LVM in AIX 4.3.1 provides a snap shot capability for raw mirrored logical
volumes. One mirror of a mirrored logical volume can be used to archive the data
on the raw logical volume without splitting the mirror copies from each other (only
the logical partitions that have changed during the system backup need to be
resynchronized).
Table 18 lists the new options added to chlvcopy command.
Table 18. chlvcopy New Options in AIX 4.3.1
Flag
Description
-b Mark a mirror copy as an online backup copy.
-c Identify which mirror copy used as on-line backup copy. The
allowed values of copy are 1, 2, or 3. If this option is not
specified, the default for copy is the last mirror copy of the
logical volume.
-B Unmark a mirror as an online backup copy.
-f Force LV copy to be marked as backup even if there are stale
partitions.
5.4.1 Removal of 1016 PPs per Physical Volume Limit (4.3.1)
The support for greater than 1016 PPs per physical volume has been added in
AIX Version 4.3.1. To support a VG exceeding the limit of 1016 PPs using the
same VGDA and VGSA areas, the number of disks supported in the volume
group has been reduced.
The -t flag was added to the chvg and mkvg commands to convert and create a
volume group with multiples of 1016 partitions per disk. This reduces the total
number of disks that can be added to the volume group by same fraction. Once a
volume group is changed or created to hold more than 1016 physical partitions
per disk, it cannot be imported into AIX versions earlier than 4.3.1.
The -t factor allows (factor * 1016) PPs per physical volume. For example, a
partition size of at least 16 MB would be needed to create a volume group with a
10 GB disk. Or with at factor size of 2, a smaller partition size of 8 MB can be
used. However, this limits the total number of disks that can be added to the
volume group. If a factor value is used, a maximum of MAXPVS/factor disks can
be included in the volume group.
Logical Volume Manager Enhancements 85