Suddenly slow backups just from one esxi host?

[lando_uk]

Everything was good until last night. All the VMs from one of my hosts now has really slow nbd backups, which causes the jobs to leak into the morning.

Normally VMs backup at about 60-70MB/s, but last night all VMs on this particular host only transferred at 3-5MB/s.

I tested with a Veeamzip. Veeamzip was getting about 6MB/s from the dodgy host, when i migrated the same VM to another it got 80MB/s.

I also tested copying a VM directly to the host and measured the vmnic0 speed (management network), it was hitting 20MB/s, but when i then copied this same VM off again, it did it really slowly - So it seems transmit is slow, yet receive is ok.

I have reset management agents on the host
/etc/init.d/hostd restart
/etc/init.d/vpxa restart

Also rebooted all the veeam proxies. But still no difference.

I think this is probably a VMware support call rather than Veeam tomorrow, but if anyone has any ideas?

Veeam 9.5U3
esxi 6.0
vcsa 6.0

[DGrinev]

What was the bottleneck before and after the issue?

Thanks!

[foggy]

Any chance it was previously using hotadd and now fails over to NBD?