Qlogic 3200 Series User Manual - Quality of Service
A–NIC Partitioning (NPAR) Overview
Quality of Service
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SN0054667-00 G
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 the
connected devices.
Each physical port on a QLogic adapter can simultaneously send and receive
data at up to 10Gbps in both directions. 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 configuring 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 specific bandwidth
to run critical applications using port partitions. The setting for a specific QoS can
resolve bottlenecks that exist when virtual machines (VMs) contend for port
bandwidth.
Enhanced transition services (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). Thus, NPAR QoS
allocations among the NIC partitions for a specific port allocate a percentage of
the non-FCoE portion of the bandwidth.
NPAR QoS allows NIC and iSCSI partitions to each allocate a minimum
guaranteed portion of the available bandwidth. However, the user interface tools
do not support setting the bandwidth limits for iSCSI partitions. Therefore, an
iSCSI partition may not get the bandwidth you require. For example, if the total
minimum allocated bandwidth across the NIC partitions equals 100 percent, then
the iSCSI partition is limited to 1 percent of the NIC bandwidth portion in
high-utilization conditions.
To ensure that iSCSI has more than one percent of bandwidth available in
high-utilization conditions, set the total NPAR QoS minimum bandwidth settings
so that they equal less than 100 percent.
For example:
An NPAR-enabled port has two NIC partitions: one iSCSI partition and one
FCoE partition.
NOTE
When bandwidth settings exist for both NPAR and DCBX, DCBX takes
precedence over NPAR. DCBX sets the bandwidth for iSCSI and NIC traffic,
and then NPAR sets the bandwidth for the NIC partitions by dividing the NIC
bandwidth allocated by DCBX. For more information, see