IBM System Storage DS3500 Introduction And Implementation Manual page 100

7914DS3KPlanning_090710.fm
Logical Volume - Iv04
LP1
PP8
PP42
Physical Volume
(/dev/hdisk9)
Figure 3-23 Relationships between LP and PP
The Logical Volume Manager controls disk resources by mapping data between a simple
and flexible logical view of storage space and the actual physical disks. The Logical
Volume Manager does this by using a layer of device driver code that runs above the
traditional physical device drivers. This logical view of the disk storage is provided to
applications and is independent of the underlying physical disk structure (Figure 3-24).
ROOTVG
ROOTVG
Physical
Partitions
Physical Volume
Figure 3-24 AIX LVM conceptual view
Best practice: When using a DS3500 Storage System with operating systems that have a
built-in LVM, or if a LVM is available, you need to make use of the LVM.
The AIX LVM provides a number of facilities or policies for managing both the performance
and availability characteristics of logical volumes. The policies that have the greatest impact
on performance in general disk environment are the intra-disk allocation, inter-disk allocation,
write scheduling, and write-verify policies.
76
IBM System Storage DS3500: Introduction and Implementation Guide
LP8 LP9
PP19
PP18
PP45
Physical
Partitions
hdisk0
Physical Volume
hdisk1
Physical
Partitions
hdisk2
Physical Volume
Draft Document for Review March 28, 2011 12:24 pm
Logical Volume - mirrlv
LP8 LP9
PP18
PP45
LP: Logical Partitions
PP: Physical Partitions
Three physical disks in the box form
a single volume group (rootvg).
Logical
Partitions
Logical Volume