Testing Jumbo Frames on the VirtuCache Replication Network
VirtuCache replicates (mirrors) the write cache over a VMware network. By default, VirtuCache uses the vMotion network for write cache replication, but you can create a new network for this purpose.
For this network, please ensure that Jumbo Frames are enabled on the vswitch, vmkernel adapter, and physical switch port for this network.
You can test if Jumbo Frames are enabled end-to-end by using the below command.
SSH to the host using Putty.
type the below command on ESXi CLI.
vmkping -I vmkXYZ -s 8972 -d IP-address
-s is the size of the packet payload. The ICMP payload is 8972 bytes, calculated using this formula: 9000 (MTU size) – 8 (ICMP header) – 20 (IP header) = 8972 bytes.
-d is to disable IP fragmentation. Very important that you do this, else all packet sizes will succeed since large packet sizes will automatically be fragmented.
-I is the vmk adapter for the outbound ICMP packet. This should be the vmk adapter used by the VirtuCache replication network.
– IP address of VirtuCache replication network on the other host(s) in the cluster.
If the above vmkping command succeeds, then Jumbo Frames are enabled end to end.