vSphere 5 and JumboFrames inside VM (UPDATED)

[Constantin (staff)]

According to VMware KB using JumboFrames inside VM is not supported in vSphere 5 with vmxnet3 network adapter. Therefore StarWind Software doesn`t support following scenarios untill VMware will not provide an updated version of VMTools:
1) Connecting with iSCSI initiator running inside VM hosted on vSphere 5 directly to StarWind iSCSI targets with JumboFrames enabled inside this VM and vmxnet3 adapter used with VMTools 5 installed. Please note: due to possible performance degradation associated with disabled Jumbo Frames the abovementioned configuration is not recommended.

Meanwhile StarWind Software fully supports and recommends following scenarios with JumboFrames enabled:
1) Using StarWind iSCSI targets as VMFS datastore
2) Using StarWind iSCSI targets as RDM (Raw Device Mapping) for VM in physical and virtual compatibility mode.
3) Using VMTools and vmxnet3 driver from vSphere 4 (can be downloaded here)
4) Connecting with iSCSI initiator running inside VM hosted on vSphere 5 directly to StarWind iSCSI targets with JumboFrames enabled inside this VM and vmxnet2 (Enhanced) or E1000 adapter used with VMTools 5 installed.

[Vladislav (Staff)]

Hi all,

According to updated VMware KB ESXi 5.0 Update 1 and higher have this issue resolved.

[pusstour]

Thanks, I will follow on this update.

[anton (staff)]

You're welcomed to post your findings / results here!

[BeverlyWiggins]

This VMware KB highlights a limitation with Jumbo Frames and the vmxnet3 adapter in vSphere 5, making it crucial to avoid unsupported configurations to prevent potential performance issues. StarWind Software provides clear alternatives, such as using VMFS datastores, RDMs, or compatible drivers like vmxnet2 or E1000, ensuring optimal performance with Jumbo Frames enabled.

[yaroslav (staff)]

Nice summary, yet vSphere 5 is already not so common.