Lenovo ThinkServer RD540 - Manual (Page 66)

8200 Series Converged Network Adapter and 3200 Series Intelligent Ethernet Adapter Page 48
Quality of Service
Quality of service (QoS) refers to the bandwidth allocation assigned to each partition used to send and
receive data between the adapter port and connected devices.
Each physical port on the 8200 and 3200 Series Adapters can send and receive data at up to 10Gbps in
both directions at the same time. When the physical port is partitioned into four partitions, the port
bandwidth is divided between each port partition according to traffic demands.
You can set QoS for each port partition by setting minimum and maximum percentages of the physical
port's bandwidth for each partition. This feature helps guarantee a transmission rate for each partition that
requires a particular bandwidth to run critical applications using port partitions. The setting for a given QoS
can resolve bottlenecks that exist when virtual machines (VMs) contend for port bandwidth.
Enhanced transition selection (ETS) controls the actual bandwidth allocation at the network port. The
bandwidth allocation under ETS is typically 50 percent for FCoE traffic and 50 percent for Non-FCoE traffic
(NIC and iSCSI). Therefore, NPAR QoS allocations among the NIC partitions for a given port allocate a
percentage of the Non-FCoE portion of the bandwidth.
NPAR QoS allows NIC partitions to each allocate a minimum guaranteed portion of the available
bandwidth. QoS bandwidth applies only to NIC partitions. iSCSI partitions are not supported by the QoS
bandwidth allocation. This brings up the possibility that, if the total minimum allocated bandwidth across
the NIC partitions equals 100 percent, then the iSCSI partition will be limited to 1 percent of the NIC
bandwidth portion in high-utilization conditions.
To ensure that iSCSI has more than 1 percent of bandwidth available in high-utilization conditions, set the
total NPAR QoS minimum bandwidth settings so that they equal less than 100 percent.
Example:
• An NPAR enabled port has two NIC partitions, one iSCSI partition, and one FCoE partition.
• ETS allocates 50 percent of the network bandwidth to FCoE traffic and 50 percent to non-FCoE traffic.
• The NPAR QoS minimum bandwidth setting for each NIC partition is 50 percent.
This setting means that each NIC partition is guaranteed 50 percent of 50 percent of 10Gb, or 2.5Gb
each.
• If at any time the FCoE partition is using 5Gb of bandwidth and each NIC partition is using 2.5Gb, then
the iSCSI partition is left with only 50Mb of bandwidth.
• If, however, the NIC partitions each allocated 45 percent of the non-FCoE traffic, then the total
allocated bandwidth would be 90 percent.
— The remaining 10 percent (or 500 Mb) would then be effectively reserved for the iSCSi partition.
eSwitch
The 8200 and 3200 Series Adapters support embedded switch (eSwitch) functionality, which provides a
basic VLAN-aware Layer-2 switch for Ethernet frames. Each physical port has one instance of an eSwitch,
which supports all NPARs on that physical port.
The eSwitch operation is transparent and the administrator does not need to perform any specific
configuration. The ability to view eSwitch statistics depends on your operating environment and
management tool.
The QLogic drivers download the VM MAC addresses to the firmware, which enables the firmware and
hardware to switch the packets destined for VMs on the host.
For traffic to flow from one eSwitch to another, it must first pass through an external switch or have been
forwarded by a VM that has a path through both eSwitches.