Deployment Guide

32 VxFlex Network Deployment Guide using Dell EMC Networking 25GbE switches and OS10EE
7 Best practices
The post-installation information that is provided in this section consists of the following:
• Increase the Maximum Transmission Unit (MTU) for VMware vSphere and Dell EMC VxFlex
• Configure Quality of Service using Differentiated Services (DiffServ)
For more information on performance tuning, including ESXi hosts and VxFlex VMs, see the VxFlex v2.x
Performance Fine-Tuning Technical Notes Guide.
7.1 Maximum Transmission Unit size
In this environment, the distributed switch is assigned an MTU value of 9000. Also, any storage-related
interface/port group has an MTU value of 9000. The following table summarizes the port groups that have an
MTU value of 9000:
VDS port groups with modified MTU values
VDS switch name
Network label
Connected port groups
MTU
atx01-w01-vds01
vMotion
atx01-w01-vds01-vMotion
9000
atx01-w01-vds01
VxFlex-data01
atx01-w01-vds01- VxFlex-data01
9000
atx01-w01-vds01
VxFlex-data02
atx01-w01-vds01- VxFlex-data02
9000
To verify that jumbo frames are working the ESXi CLI tool vmkping is used. After establishing an SSH
connection with atx01w01esx01, a non-defragment capable ping with an MTU value of 8972 is sent from the
host using the data01 VMkernel adapter to atx01w01esx02.dell.local.
Note: The maximum frame size that vmkping can send is 8972 due to IP (20 bytes) and ICMP (8 bytes)
overhead.
[root@atx01w01esx01:~] vmkping -d -s 8972 –I vmk2 172.16.34.106
PING 172.16.34.102 (172.16.34.102): 8972 data bytes
8980 bytes from 172.16.34.106: icmp_seq=0 ttl=64 time=0.360 ms
8980 bytes from 172.16.34.106: icmp_seq=1 ttl=64 time=0.373 ms
8980 bytes from 172.16.34.106: icmp_seq=2 ttl=64 time=0.451 ms