IBM System Storage DS3500 Introduction And Implementation Manual page 671

Draft Document for Review March 28, 2011 12:24 pm
Planning for single Virtual I/O Server
The Figure 21-1 on page 647 shows the recommended scenario for a single Virtual I/O
Server solution. This scenario was not supported previously for RDAC because each HBA
controller could not have access to both storage controllers. The Virtual I/O Server can
provide a virtual disk for each AIX client partition by sharing a single physical disk with the
clients or assign an entire physical disk dedicated to each client partition.
Client Partition
Figure 21-1 Single VIO configuration with MPIO
The Virtual I/O Server gives the ability to create multiple (boot or data) disks from a single
physical disk in order to provide virtual disks for the logical partitions. The backing devices for
the virtual disks can be logical volumes and SAN logical drive devices. These choices can be
mixed and matched. The Virtual I/O Server is not limited to using just one type of backing
storage device.
If using logical volumes for the backing storage device, on the Virtual I/O Server, a
volumegroup (or storage pool in the case of Integrated Virtualization Manager systems) is
created from one or more available physical volumes. Logical volumes are created on the
volume group. Those logical volumes get mapped to the client partitions as virtual disks, one
logical volume for each virtual disk. When creating the logical volume, the size specified for
the logical volume will become the size of the virtual disk. This gives the flexibility to
effectively use a few disk drives to support multiple partitions.
Physical volumes are preferred when there is enough space, and performance becomes a
priority. If using a whole physical disk for a backing device for your virtual disks, it is necessary
to use a disk that the Virtual I/O Server has not assigned to a volume group. This allows client
partitions to share the physical storage controller and also use full performance of a physical
Virtual SCSI Disk Drive (hdisk0)
vSCSI Client adapter (vscsi0)
VIO1
vSCSI Server adapter (vhost0)
MPIO FC SCSI Disk Drive (hdisk0)
MPIO
FC protocol driver (fscsi0) FC protocol driver (fscsi1)
FC Adapter (fcs0)
SAN Switch
Controller A (dac0)
Logical Drive
DS3500 (dar0)
FC Adapter (fcs1)
SAN Switch
Controller B (dac1)
Chapter 21. AIX 6.1 configuration guide
AIX.fm
647