NSX-T Networking Best Practices

NSX-T Networking Best Practices
NSX-T Networking Best Practices
NSX-T 1.1
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NSX-T Networking Best Practices Guide
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Contents
NSX-T NETWORKING BEST PRACTICES.....................................................................................4
1 HARDWARE RECOMMENDATIONS ......................................................................................5
NIC CONSIDERATIONS ....................................................................................................................... 5
MTU SIZE ....................................................................................................................................... 6
DEDICATED HOST FOR BRIDGE ............................................................................................................ 6
BIOS SETTINGS ................................................................................................................................ 7
2 ESXI NETWORKING RECOMMENDATIONS ...........................................................................8
VSPHERE VERSION RECOMMENDATION ................................................................................................ 8
PHYSICAL NIC CONFIGURATION .......................................................................................................... 9
Receive Side Scaling (RSS)........................................................................................................ 9
Queue Size ............................................................................................................................. 11
VIRTUAL NIC CONFIGURATIONS........................................................................................................ 12
Interrupt Coalescing .............................................................................................................. 12
Receive Side Scaling (RSS)...................................................................................................... 13
Queue Size ............................................................................................................................. 14
SPLITRX MODE .............................................................................................................................. 14
Disable SplitRx Mode for an ESXi Host .................................................................................. 14
Enable or Disable SplitRx Mode for a Virtual NIC .................................................................. 15
MULTIPLE TX WORLDS .................................................................................................................... 15
Change Tx World Value ......................................................................................................... 15
PERFORMANCE TUNING FOR DIFFERENT WORKLOADS .......................................................................... 16
Latency Sensitive Workloads ................................................................................................. 16
Telco and NFV Workloads...................................................................................................... 16
3 KVM NETWORKING RECOMMENDATIONS .........................................................................17
LINUX VERSION RECOMMENDATION.................................................................................................. 17
LINUX HYPERVISOR CONNECTION TRACKING ....................................................................................... 17
PHYSICAL NIC CONFIGURATION ........................................................................................................ 17
HANDLING NETWORK INTERRUPTS FROM PHYSICAL NICS ..................................................................... 18
VIRTUAL NIC CONFIGURATION ......................................................................................................... 18
Enable Multi-Queue Virtio for Virtual NICs ........................................................................... 18
Queue Size ............................................................................................................................. 19
4 MANAGEMENT PLANE AND CONTROL CLUSTER PLANE RECOMMENDATIONS ..................... 20
LOGICAL SWITCH AND DFW RULES ................................................................................................... 20
REFERENCES ........................................................................................................................ 21
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NSX-T Networking Best Practices
The NSX-T Networking Best Practices Guide, provides best practice recommendations and
configuration instructions to enhance NSX-T performance.
Intended Audience
This information is intended for anyone who wants to maximize the NSX-T network
performance. This information is written for experienced system administrators who are
familiar with virtual machine technology, virtual networking, and virtual datacenter
operations.
This manual assumes familiarity with a virtual machine management service—such as
VMware vSphere 6.5, 6.0 or 5.5, including VMware ESX, vCenter Server, and the
vSphere Web Client, VMware Tools—or another virtual machine management service
with kernel-based virtual machines (KVMs).
VMware Technical Publications Glossary
VMware Technical Publications provides a glossary of terms that might be unfamiliar to
you. For definitions of terms as they are used in VMware technical documentation, go to
http://www.vmware.com/support/pubs.
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1 Hardware Recommendations
Before you undertake network optimization effort, you must understand the physical aspects of
the network. Consider implementing the following hardware on your physical layout:
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Server-class network interface cards (NICs) for best performance
Latest drivers for NICs
Latest firmware version for ESX
Network infrastructure between the source and destination NICs should not introduce
bottlenecks.
For example, if both NICs are 10Gb/s, all the cables and switches must be of the same
speed and the switches must not be configured to a lower speed.
NIC Considerations
For the best network performance, use NICs that support specific hardware features and that
support offloads of encapsulated packets.
To find out supported offloads for an adapter ( IPv4 and IPv6), see the product specification or
datasheet provided by the adapter vendor, or refer to the IO compatibility guide [4].
Supported NIC Features
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Checksum offload (CSO)
TCP segmentation offload (TSO)
UDP Checksum offload (CSO)
Encapsulated Packets (Overlay)
● Geneve TCP/UDP Checksum offload (CSO)
● Geneve TCP segmentation offload (TSO)
● Geneve Rx filter
Geneve OAM packet filter
Ability to handle high-memory DMA (64-bit DMA addresses)
Ability to handle multiple Scatter Gather elements per Tx frame
Jumbo frames (JF)
Receive Side Scaling (RSS)
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Network cards must be installed in slots with enough bandwidth to support their maximum
throughput.
PCI Slots
NIC
PCIe x8 or later
Single-port 10Gb/s
PCI-X 266
Single-port 10Gb/s
PCIe x16 or later
Dual-port 10Gb/s
PCIe 2.0
Number of lanes (x8 or x16) can be reduced
accordingly. There should be no bridge chip
in the path to the actual Ethernet device such
as, PCI-X to PCIe or PCIe to PCI-X.
Determine that there are no embedded bridge
chips on the device which can reduce
performance.
PCI Gen3 x8 slots or later
PCI Gen3 x16 slots or later
40Gb/s
100Gb/s
Multiple physical NICs between a virtual switch (vSwitch) and the physical network constitute a
NIC team. NIC teams can provide passive failover in the event of hardware failure or network
outage. In some configurations, NIC teams can increase performance by distributing the traffic
across those physical NICs.
When you use load balancing across multiple physical NICs connected to one vSwitch, all the
NICs should have the same line speed.
If the physical network switch to which your physical NICs are connected supports Link
Aggregation Control Protocol (LACP), configuring both the physical network switches and the
vSwitch to use LACP can increase throughput and availability.
MTU Size
To support overlay traffic, NSX-T supports the MTU size of 1600B (1500B with 100 extra bytes
for encapsulation) or larger on all the components. Recommended minimum MTU size is 1600B.
Dedicated Host for Bridge
A bridge provides connectivity between overlay traffic and VLAN traffic. It is recommended to
use a dedicated host if a bridge is configured on that host since the workload can be high.
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BIOS Settings
The default hardware BIOS settings on servers might not always be the best choice for optimal
performance. When you configure a new server check the BIOS settings.
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Run the latest version of the BIOS available for your system.
BIOS must enable all populated processor sockets and all the cores in each socket.
Enable the Turbo Boost in the BIOS if your processors support it.
Select High Performance Profile in the BIOS setting for CPU to allow maximum CPU
performance. Note that this might increase power consumption.
Some NUMA-capable systems provide an option in the BIOS to disable NUMA by
enabling node interleaving. In most cases, disabling the node interleaving and leaving
NUMA enabled is better for performance.
Enable hardware-assisted virtualization features such as, VT-x, AMD-V, EPT, RVI in the
BIOS.
If the BIOS allows the memory scrubbing rate to be configured, keep the manufacturer
default setting.
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2 ESXi Networking
Recommendations
Consider the guidance provided for ESXi network optimization.
vSphere Version Recommendation
For best performance with NSX-T, use vSphere 6.5 which includes the following key features:
●
Uplink SW LRO support has a significantly improved performance for firewall and
available by default.
This feature can be used with NICs that support NetQueue with VLAN Traffic and the
NICs that support Geneve Rx filter for Geneve Traffic. Uplink SW LRO aggregate
packets as soon as the physical NIC receives it to reduce the number of packets processed
by the networking stack.
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ESXi pNIC offload support for Geneve is enhanced in the vSphere 6.5 release.
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8
Features
vSphere 6.0 and
Update releases
vSphere 6.5 (2016)
Inner frame TCP/UDP CSO/TSO
and software emulation
Yes (*)
Yes
Outer UDP checksum offload and
software emulation
No
Yes
Geneve Rx filter
No
Yes
Geneve OAM queue for
management traffic
No
Yes
(*) The TSO support in vSphere 6.0 has some limitation. If NICs have constraints in
number of SG elements in DMA engine such as, i40e driver, maximum L2 payload size
and maximum MSS size, this combination is not supported in vSphere 6.0.
Support of multiple Tx worlds which improves packet transmission performance by using
more worlds to process packets from a particular vNIC queue.
Split Rx mode will have a dedicated kernel thread for Receive Processing in vSphere 6.5.
In the prior vSphere releases, SplitRx mode used to share the VM/VNIC Tx Processing
thread for doing Receive processing for the VNIC.
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Physical NIC Configuration
You can configure the supported physical NIC configurations for NSX-T to tune the
performance.
Receive Side Scaling (RSS)
Receive Side Scaling (RSS) allows network packets from a NIC to be processed in parallel on
multiple CPUs by creating a different thread for each hardware queue. ESX supports two
variations of RSS - NetQueue and Device. When used in NetQueue mode which is default, ESX
controls how traffic is distributed to multiple hardware queues. In Device RSS mode, hardware is
in complete control of how traffic is distributed to multiple hardware queues.
NetQueue
NetQueue is a logical queue concept unique to ESXi that can be mapped to one or more hardware
queues. By default, each logical queue maps to single hardware queue and there is a single thread
processing that queue. NetQueue redirects traffic so that packets destined to a certain VM are
distributed to the same NetQueue. NetQueue allows data interrupt processing to be affinitized to
the CPU cores associated with individual VMs, improving receive-side networking performance
by providing better NUMA locality.
Some pNIC drivers also support a feature called queue pairing. Queue pairing indicates to the
ESXi uplink layer that the receive thread (NetPoll) also processes completion of transmitted
packets on a paired transmit queue. This feature could even further improve the CPU efficiency.
To disable queue pairing use the command,
# esxcli system settings advanced set -o
/Net/NetNetqRxQueueFeatPairEnable -i 0
In the NetQueue model, there is a default queue and single or multiple non-default queues. All
Broadcast / Unknown unicast / Multicast (BUM) traffic is handled by the default NetQueue.
Based on the load balance algorithm, traffic destined to a VM can be redirected to a non-default
queue by pushing down the VM’s MAC address as the filter to the physical queue on the NIC.
In the NSX overlay environment, the VM MAC address might not be seen by the NIC because it
is encapsulated. There are some NICs that support Rx filter for encapsulated traffic (Geneve Rx
filter) and can see inner MAC. In that case, NetQueue works well for encapsulated packets.
However, when the NIC can only see the outer MAC address which is VTEP’s MAC address, all
overlay traffic destined to this VTEP is redirected to a single NetQueue. To improve the
scalability for encapsulated traffic in the absence of Geneve Rx filter, NetQueue RSS was
introduced.
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NetQueue RSS
When NetQueue RSS is enabled, there is a special NetQueue created called NetQueue RSS,
which is associated with up to four hardware queues. Overlay traffic can be redirected to the
NetQueue RSS and further distributed to multiple hardware queues based on 5-tuple hash. While
this might increase network throughput for a NIC that receives packets at a high rate, it can also
increase CPU overhead since there is NUMA locality loss.
The command to enable NetQueue RSS is device specific, please refer to device driver manual
for each device to enable it.
Default Queue RSS
All BUM Traffic is handled by the default queue. Default queue is backed by single hardware
queue and is serviced by a single thread by default. This could result in performance degradation
for certain hosts which received a lot of BUM traffic. To overcome this limitation, vSphere 6.0 or
vSphere 6.5 later version (depending on driver type used) has introduced Default Queue RSS.
When Default Queue RSS enabled, default queue is serviced by multiple hardware queues. All
the traffic it receives is distributed among different hardware queues which are serviced by
different hypervisor threads.
Default Queue RSS is useful for high broadcast/multicast traffic or for appliances that process
packets on multiple MAC addresses which are unknown to the hypervisor such as, VMs on
promiscuous mode and other gateway appliances.
Enable Default Queue RSS
You can enable the Default Queue RSS for bnx2x NICs.
Procedure
1. Open a command prompt.
2. Enable Default Queue RSS by configuring the module load parameter.
esxcfg-module -s "rss_on_default_queue=1
num_queues_on_default_queue=4" bnx2x
Device Mode RSS
vSphere 6.0 and vSphere 6.5 depending on the driver type has support for Device Mode RSS,
which is an RSS feature on NIC. For the Device Mode RSS, the device controls all the hardware
queues. A NIC uses the RSS engine to drive traffic among multiple queues.
The Device Mode RSS is recommended when you configure bridge or Edge on the transport
node. The Device Mode RSS has two disadvantages.
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All queues are used irrespective of traffic load. When there is a low network traffic,
this traffic that could be serviced by fewer queues is distributed among all queues
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instead. This results in a higher interrupt rate as each queue generates its own
interrupts.
The unicast traffic for one VM can be serviced by multiple queues, which results in
loss of locality especially for NUMA. VMs are placed on the same NUMA node
where the thread servicing the traffic is placed. With Device Mode RSS, all VMs
share all queues and therefore, cannot get proper isolation.
The command to enable NetQueue RSS is device specific, please refer to device driver manual
for each device to enable it.
RSS Recommendation Summary
NetQueue non-RSS mode is enabled by default. All other features must be enabled explicitly.
NetQueue
VLAN Traffic
Overlay Traffic
Yes for unicast
traffic
Yes, if Geneve RX
filter is supported
Yes, if Geneve RX
filter is NOT supported
NetQueue RSS
NetQueue
Mode RSS
Default queue
RSS
Bridging Traffic
Yes for BUM
traffic
Device Mode RSS
Yes
Yes, if default
queue RSS is
NOT available
Queue Size
The ESXi uplink pNIC layer also maintains a software Tx or Rx queue of packets queued for
transmission or reception, which by default holds 500 packets. If the workload is I/O intensive
with large bursts of packets, this queue may overflow leading to packets being dropped in the
uplink layer.
Increase Queue Size
You can increase the queue size up to 10,000 packets.
Depending on the physical NIC and the specific version of the ESXi driver being used on the
ESXi host, packets can be dropped in the pNIC driver because the transmit or reception ring on
the pNIC is too small and is full.
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Procedure
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Increase the queue size for Tx or Rx.
# esxcli system settings advanced set -i 10000 -o
/Net/MaxNetifTxQueueLen
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Increase the size of the ring in the pNIC drivers for Tx.
# ethtool -G vmnic0 tx 4096
This command increases the Tx ring size to 4096 entries.
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Determine the maximum size you can set for a specific pNIC driver and current Tx ring.
# ethtool -g vmnic0
Ring parameters for vmnic0:
Pre-set maximums:
RX: 4096 RX Mini: 0
RX Jumbo: 0
TX: 4096
Current hardware settings:
RX: 512
RX Mini: 0
RX Jumbo: 0
TX: 4096
Virtual NIC Configurations
For the best virtual NIC performance, use the VMXNET3 paravirtualized network adapter for the
supported operating systems. The virtual machine must use virtual hardware version 7 or later
and, in some cases, VMware Tools be installed in the guest operating system.
Interrupt Coalescing
Virtual network interrupt coalescing can reduce the number of interrupts posted to VM to
decrease CPU utilization. The reduction in virtual networking overhead might allow more virtual
machines to run on a single ESXi host. Virtual network interrupt coalescing might increase
network latency from a few hundred microseconds to a few milliseconds. Many workloads are
not impacted by the additional network latency.
Virtual network interrupt coalescing is enabled for all virtual NICs in ESXi by default. For
VMXNET3 virtual NICs, you can be disable or set to a static value by changing the
ethernetX.coalescingScheme variable.
Disabling virtual interrupt coalescing increases interrupts to increase CPU utilization. It might
also lower network latency.
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Setting virtual network interrupt coalescing to a static value causes ESXi to queue a predefined
number of packets before interrupting the virtual machine or transmitting the packets. When set
to static, ESXi queues up to 64 packets by default. This value can be changed between one and 64
in the ethernetX.coalescingParams variable.
Increasing the queue size can reduce the number of context switches between the virtual machine
and the VMkernel, reducing CPU utilization in the virtual machine and VMkernel.
ESXi waits for a maximum of four milliseconds before sending an interrupt or transmitting the
packets. Other events, such as idle virtual machine might also trigger virtual machine interrupts or
packet transmission, so packets are rarely delayed the entire four milliseconds.
Disable Virtual Interrupt Coalescing
You can disable virtual interrupt coalescing for VMXNET3 virtual NIC or change the scheme
and parameters from the vSphere Client.
Procedure
1.
2.
3.
4.
5.
6.
7.
8.
9.
Log in to the vSphere Client.
Select the virtual machine to configure.
Click Edit virtual machine settings.
Under the Options tab, select General > Configuration Parameters.
Locate the ethernetX.coalescingScheme variable.
If the variable is not available, click Add Row and type
ethernetX.coalescingScheme.
Disable the ethernetX.coalescingScheme variable to disable virtual interrupt coalescing.
Where X is the number of the NIC.
Set the ethernetX.coalescingScheme variable to desired scheme name.
For example, set the name to rbc for rate based coalescing.
Where X is the number of the NIC.
Change the value of ethernetX.coalescingParams to desired value.
For example, set the value to 16000 for rbc.
Restart the virtual machine.
Receive Side Scaling (RSS)
VMXNET3 devices support multiple queues for many guest operating systems that natively
support RSS. The supported guest operating systems include Windows Server 2003 SP2 or later,
Windows 7 or later, and some Linux distributions.
VMXNET3 drivers in the vSphere 5.0 and later versions of VMware Tools and VMXNET3
drivers included with Linux kernel 2.6.37 and later have multiple receive queues enabled by
default. See, KB article 2020567.
When multiple receive queues are enabled, RSS configures the virtual machine to receive from 1,
2, 4, or 8 queues. It will choose the largest of these values that is less than or equal to the number
of vCPUs in that virtual machine.
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On Windows, the default number of transmit queues is one regardless of the number of receive
queues. If the driver is configured to use multiple transmit queues, the number of transmit queues
is the same as the number of receive queues.
On Linux, the default number of transmit queues is the same as the number of receive queues.
To obtain maximum performance for your workloads and resource availability you can add
different values for the receive queues, the value must be set to a power of two and can be a
maximum of 8 or the number of vCPUs, whichever is lower. You can also configure the driver to
use multiple transmit queues. With the exception in Linux, where the number of transmit queues
matches the number of receive queues. You can modify the settings in the advanced driver
configuration tab within the guest operating system.
Queue Size
Overflowing receive queue in the receiver network device can cause low receive throughput in a
virtual machine. If the receive buffers in the guest operating system network driver are
insufficient, packets are dropped in the VMkernel. The dropped packets degrade the network
throughput. You can increase the number of the receive buffers, which might increase the host
physical CPU workload.
For VMXNET3, the default value of the receive and transmit buffers is controlled by the guest
driver. The maximum possible value for the receive and transmit buffers is 4096. To modify the
default values within the guest, you can use the ethtool utility in Linux and configure the Device
Properties in Windows. See, KB article 1010071.
SplitRx Mode
SplitRx mode uses multiple physical CPUs to process network packets received in a single
network queue to significantly improve network performance for certain workloads. These
workloads include:
•
•
For multiple virtual machines on an ESXi host receiving multicast traffic from the same
source, the SplitRx mode improves throughput and CPU efficiency for these workloads.
For traffic using the vNetwork Appliance or DVFilter API between two virtual machines
on the same ESXi host, the SplitRx mode improves throughput and maximum packet
rates for these workloads.
In vSphere 5.1 and later, SplitRx mode is enabled for the VMXNET3 virtual NIC, which is the
only adapter type it is supported. The ESXi host detects the network queue on a physical NIC that
is heavily utilized and getting more than 10,000 broadcast/multicast packets per second.
Disable SplitRx Mode for an ESXi Host
For better CPU efficiency, for example when the packet rate received from the queue is low the
SplitRx mode can be disabled for an ESXi host from the vSphere Client.
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Procedure
1.
2.
3.
4.
5.
Select the ESXi host to disable.
Under the Configuration tab, in the Software pane, click Advanced Settings.
Locate the NetSplitRxMode variable.
Click the value.
Set the NetSplitRxMode value to 0 to disable the SplitRx mode for the ESXi host.
The default value is 1, which enables the SplitRx mode for the ESXi host.
This change is immediate and does not require the ESXi host to be restarted.
Enable or Disable SplitRx Mode for a Virtual NIC
The SplitRx mode can be configured on each virtual NIC to override the global NetSplitRxMode
variable setting from the vSphere client.
Procedure
1.
2.
3.
4.
Select the virtual machine to configure.
Click Edit virtual machine settings.
Under the Options tab, select General > Configuration Parameters.
Locate the ethernetX.emuRxMode variable.
Where X is the number of the virtual NIC. If the variable is not available, click Add Row
and type ethernetX.emuRxMode.
5. Click the value.
6. Set the ethernetX.emuRxMode value to 0 to disable the SplitRx mode for ethernetX.
The default value is 1, which enables the SplitRx mode for ethernetX.
7. Save the changes.
● Restart the virtual machine.
● Disconnect and reconnect the virtual NIC from the virtual machine.
Multiple Tx Worlds
vSphere by default configures 1 helper world for a VM to handle transmit traffic which is
sufficient for most workloads. For certain workloads which require high packet rate transmits
such as NSX Edge, vSphere has a special configuration to enable either 1 helper world per vNIC
or 1 helper world per vNIC queue. vSphere 6.5 supports the 1 helper world per vNIC queue.
vSphere 5.0 and later support the helper world per vNIC option.
Change Tx World Value
When net-stats show the Tx world runs at 100% for a VM, you might want to change this option
to use more Tx worlds.
Procedure
1. Navigate to the vsi node /config/Net/intOpts/NetVMTxType.
2. Set the node value to 2 to configure a helper world for each vNIC Tx queue.
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Performance Tuning for Different Workloads
Consider performance guidance for latency sensitive, Telco, and NFV workloads.
Latency Sensitive Workloads
To support virtual machines with strict latency requirements, vSphere 5.5 has a per-VM feature
called Latency Sensitivity. Among other optimizations, this feature allows virtual machines to
exclusively own physical cores to avoid overhead related to CPU scheduling and contention.
Combined with a passthrough functionality, which bypasses the network virtualization layer,
applications can achieve near-native performance in both response time and jitter. [1]
Telco and NFV Workloads
The vSphere ESXi hypervisor provides a high-performance and competitive platform that
effectively runs many Tier 1 application workloads in virtual machines. By default, ESXi has
been heavily tuned for driving high I/O throughput efficiently by utilizing fewer CPU cycles and
conserving power, as required by a wide range of workloads.
Telco and NFV application workloads are different from the typical Tier I enterprise application
workloads, they tend to be any combination of latency sensitive, jitter sensitive, or demanding
high packet rate throughputs or aggregate bandwidth, and need to be tuned for best performance
on vSphere ESXi. [2]
To see how the feature configuration recommendations for physical NICs included in this section
affect performance, please refer to [3].
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3 KVM Networking
Recommendations
Consider the guidance provided for KVM network optimization.
Linux Version Recommendation
Use the NSX-T supported Linux distribution, to take advantage of the performance
improvements.
Check to see if your kernel, driver, and NIC support networking capabilities such as tunnel
offloads and RSS.
Linux Hypervisor Connection Tracking
Distributed firewall (DFW) uses Linux conntrack for connection tracking. For workloads that
require a high connection rate, where new connections are setup and removed rapidly over a
sustained period, it is possible that the conntrack table gets full.
When the table is full conntrack generates the warning message, nf_conntrack: table
full, dropping packet in the system log.
Procedure
●
Set the variable timeout value.
sysctl -w
net.netfilter.nf_conntrack_tcp_timeout_time_wait=0
Physical NIC Configuration
To configure your NIC device for high performance, refer to the recommendations of your NIC
vendor.
The details depend on the particular NIC device. Typical performance recommendations include
RSS hashing configuration, number of queues, size of queues, interrupt coalescing, etc.
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Handling Network Interrupts from Physical NICs
High-performance NICs support multiple queues for packet handling. Network traffic is hashed
into multiple queues to be processed by multiple CPU cores concurrently.
A Linux kernel process called irqbalance maps interrupt requests (IRQ) associated with the NIC
queues to the available CPU cores. For network intensive workloads you can modify the default
behavior and map device IRQs to specific CPU cores.
To stop the irqbalance service, use the service stop irqbalance command.
To set affinity of the NIC device IRQs to specific CPU cores, check if your NIC driver has an
available script. Use the command, ./<path-to-NIC-driverscripts>/set_irq_affinity.sh <devname> to run the script.
To improve performance, you can set the device IRQ affinity so that NIC interrupts are handled
by CPU cores on the same NUMA node as the device. Use the command,
cat /sys/class/net/<devname>/device/numa_node to find the NUMA node of
the device.
Virtual NIC Configuration
Consider the virtual NIC configuration guidance for better performance.
Enable Multi-Queue Virtio for Virtual NICs
Multi-queue virtio-net provides enhanced network performance for a guest VM by allowing
packet-processing ability to scale with the number of vCPUs.
Prerequisite
Verify that your operating system has support for multi-queue virtio.
Procedure
1. Open the guest XML configuration file.
2. Add XML code.
<interface type=’....’>
<model type=’virtio’/>
<driver name=’vhost’ queues=’N’/>
</interface>
Where N is the number of vCPUs assigned to the guest VM.
3. In the virtual machine, enable multi-queue virtio support.
# ethtool -L ethX combined N
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Queue Size
You can improve the throughput by increasing the txqueuelen value of the interface when the
interface is connected to a high-speed network link.
You can experiment with modifying the default txqueuelen value to see if performance improves
for your workload. For example, #ifconfig ethX txqueuelen 10000 sets the
txqueuelen value to 10000. Using a large txqueuelen value might increase the end-to-end packet
latency.
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4 Management Plane and Control
Cluster Plane Recommendations
The Management Plane and Control Cluster Plane appliances must have sufficient CPU, memory,
and storage resources for capacity and performance for your deployment size.
See the NSX-T Installation guide.
The NSX-T performance is dependent on the number of managed entities such as hosts and
virtual machines. Exceeding the maximum specified in the NSX-T Configuration Maximums, is
not supported and impacts performance.
Since the Management Plane and the Control Plane Appliances are distributed, as a best practice
run them on different rack servers but refrain from having high network latency between them.
Logical Switch and DFW Rules
The Management Plane and the Control Plane aggregate before communicating between each
other.
●
●
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As a best practice, configure all the logical switches in parallel before configuring the
ports. Logical switch realization is batched and can decrease the deployment time if all of
the logical switches are realized before ports are connected.
Distributed Firewall rules should be consolidated into sections and it is recommended to
minimize the number of sections.
VMware, Inc.
NSX-T Networking Best Practices Guide
References
[1] Deploying Extremely Latency-Sensitive Applications in VMware vSphere 5.5
http://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/techpaper/latencysensitive-perf-vsphere55-white-paper.pdf
[2] Best Practices for Performance Tuning of Telco and NFV Workloads in vSphere
http://www.vmware.com/techpapers/2015/best-practices-for-performance-tuning-of-telcoand-10479.html
[3] Leveraging NIC Technology to Improve Network Performance in VMware vSphere
http://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/whitepaper/vmwarevsphere-pnics-performance-white-paper.pdf
[4] VMware Compatibility Guide
https://www.vmware.com/resources/compatibility/search.php?deviceCategory=io
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VMware, Inc.
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