Specifications

5102ch03.fm Draft Document for Review May 12, 2014 12:46 pm
90 IBM Power System S822 Technical Overview and Introduction
within the set of micropartitions are monitored by the POWER Hypervisor, and processor
capacity is managed according to user-defined attributes.
If the Power Systems server is under heavy load, each micropartition within a shared
processor pool is guaranteed its processor entitlement plus any capacity that it might be
allocated from the reserved pool capacity if the micropartition is uncapped.
If certain micropartitions in a shared processor pool do not use their capacity entitlement, the
unused capacity is ceded and other uncapped micropartitions within the same shared
processor pool are allocated the additional capacity according to their uncapped weighting. In
this way, the entitled pool capacity of a shared processor pool is distributed to the set of
micropartitions within that shared processor pool.
All Power Systems servers that support the multiple shared processor pools capability have a
minimum of one (the default) shared processor pool and up to a maximum of 64 shared
processor pools.
For more information and requirements about the shared storage pool, see the following
publication: IBM PowerVM Virtualization Introduction and Configuration, SG24-7490.
3.4.4 Virtual I/O Server
The Virtual I/O Server is part of all PowerVM editions. It is a special-purpose partition that
allows the sharing of physical resources between logical partitions to allow more efficient
utilization (for example, consolidation). In this case, the Virtual I/O Server owns the physical
resources (SCSI, Fibre Channel, network adapters, and optical devices) and allows client
partitions to share access to them, thus minimizing the number of physical adapters in the
system. The Virtual I/O Server eliminates the requirement that every partition owns a
dedicated network adapter, disk adapter, and disk drive. The Virtual I/O Server supports
OpenSSH for secure remote logins. It also provides a firewall for limiting access by ports,
network services, and IP addresses. Figure 3-9 shows an overview of a Virtual I/O
Server configuration.
Figure 3-9 Architectural view of the Virtual I/O Server
Virtual I/O Server
Hypervisor
Shared Ethernet
Adapter
Physical Ethernet
Adapter
Physical Disk
Adapter
Virtual I/O Client 1
Virtual Ethernet
Adapter
Virtual SCSI
Adapter
Virtual I/O Client 2
Virtual Ethernet
Adapter
Virtual SCSI
Adapter
Virtual Ethernet
Adapter
Virtual SCSI
Adapter
Physical
Disk
Physical
Disk
External Network