Learn about Virtual I/O Server configuration
limitations.
Consider the following when implementing virtual SCSI:
- Virtual SCSI supports the following connection standards for backing
devices: fibre channel, SCSI, SCSI RAID, iSCSI, SAS, SATA, USB, and
IDE.
- The SCSI protocol defines mandatory and optional commands. While
virtual SCSI supports all of the mandatory commands, not all of the
optional commands are supported.
- There are performance implications when you use virtual SCSI devices.
Because the client/server model is made up of layers of function,
using virtual SCSI can consume additional processor cycles when processing
I/O requests.
- The Virtual I/O Server is
a dedicated logical partition, to be used only for Virtual I/O Server operations.
Other applications cannot run in the Virtual I/O Server logical partition.
- If there is a resource shortage, performance degradation might
occur. If a Virtual I/O Server is
serving many resources to other logical partitions, ensure that enough
processor power is available. In case of high workload across virtual
Ethernet adapters and virtual disks, logical partitions might experience
delays in accessing resources.
- Logical volumes and files exported as virtual
SCSI disks are always configured as single path devices on the client
logical partition.
- Logical volumes or files exported as virtual
SCSI disks that are part of the root volume group (rootvg) are not
persistent if you reinstall the Virtual I/O Server. However, they
are persistent if you update the Virtual I/O Server to a new service
pack. Therefore, before reinstalling the Virtual I/O Server, ensure that
you back up the corresponding clients' virtual disks. When exporting
logical volumes, it is best to export logical volumes from a volume
group other than the root volume group. When exporting files, it is
best to create file storage pools and the virtual media repository
in a parent storage pool other than the root volume group.
Consider the following when implementing virtual adapters:
- Only Ethernet adapters can be shared. Other types of network adapters
cannot be shared.
- IP forwarding is not supported on the Virtual I/O Server.
- The maximum number of virtual adapters can be any value from 2
to 65,536. However, if you set the maximum number of virtual adapters
to a value higher than 1024, the logical partition might fail to activate
or the server firmware might require more system memory to manage
the virtual adapters.
The Virtual I/O Server supports
client logical partitions running the following operating systems
on the following POWER6™ processor-based
servers.
Table 1. Operating system support for Virtual I/O Server client logical
partitions| Operating system |
POWER6 processor-based
servers |
|---|
| AIX® 5.3 or
later |
All POWER6 processor-based
servers |
| IBM® i 6.1 or later |
All POWER6 processor-based
servers |
| SUSE Linux® Enterprise Server 10 Service
Pack 2 or later |
|
| SUSE Linux Enterprise Server 10 Service
Pack 1 |
- 8203-E4A
- 8204-E8A
- 9117-MMA
- 9406-MMA
- 9407-M15
- 9408-M25
- 9409-M50
|
| Red Hat Enterprise Linux version
5.2 |
|
| Red Hat Enterprise Linux version
5.1 |
- 8203-E4A
- 8204-E8A
- 9117-MMA
- 9406-MMA
- 9407-M15
- 9408-M25
- 9409-M50
|
| Red Hat Enterprise Linux version
4.7 |
9119-FHA |
| Red Hat Enterprise Linux version
4.6 |
9125-F2A |
| Red Hat Enterprise Linux version
4.5 |
- 8203-E4A
- 8204-E8A
- 9117-MMA
- 9406-MMA
- 9407-M15
- 9408-M25
- 9409-M50
|
The Virtual I/O Server supports
client logical partitions running the following operating systems
on POWER5™ processor-based
servers:
- AIX 5.3 (or
later)
- SUSE Linux Enterprise Server 9 (or
later)
- SUSE Linux Enterprise Server 10 (or
later)
- Red Hat Enterprise Linux version 4 (or
later)
- Red Hat Enterprise Linux version
5 (or later)