VMXNET 3 adapter safe but slow...?

[ikt]

Hi,

We use the latest, updated VSphere 5.5 version

For (decades:-) we have run our VMWare environment smoothly without major problems.  However early this year we discoveres infrequent network interface disconnections for some of the virtual machines. The incidents were rare, but I googled the problem and found that it was recommended to switch to the VMXNET 3 adapter type.  So we did, and the disconnection (cable unplugged) problem went away.  However we experience that the system is much slower now than before, and we suspect that this problem started with the change of network adapter type.

Now what is the difference between the VMXNET 3 adapter and the 'original' E1000E adapter?

Why did we suddenly start to get 'cable unplugged' errors with the E1000E adapters on some VMs, the only cables involved are virtual...

Btw we still maintain the e1000e adapter type for our iSCSI interfaces.

Thanks for comments and suggestions what to try to get our system optimized again...

regards Tor

[antonmajor]

By design, the vmxnet 3 adapter utilizes cpu cycles to transmit data to/from other virtual machines located on the same host. If you have only one host with all your vm's and are seeing a significant slowdown, you may want to take a look if you over allocated CPU and ensure that ESXI itself has enough overhead to survive.