I've got some Veeam backups proxies that are nothing but Ubuntu servers with a small Veeam package installed. I've been having issues with extremely slow Veeam backups but I haven't been able to find the root cause. I ran iperf tests from the Veeam server to the backup proxies, both of which have 10Gb network connections and I got about 5Gb/s. That's not bad considering there's other traffic on those 10Gb NICs on the hosts.
Here's the insanity I can't wrap my feeble brain around. I ran an iperf test from one of the VMs to it's host and I'm getting less than 4Mb/s (see below). How is this possible and what can I do to resolve the issue? The VM is configured with a VMXNET 3 adapter running at 10Gb. The NIC for that VM is is on the same vSwitch as the iSCSI and vSAN traffic are using but the 10Gb active physical switch port for that vSwitch on that host is running at less than 2% capacity. I understand the VM is connected to a virtual switch but I wanted to include the information about the physical switch in case it was important in a way I'm not aware of.
Connecting to host 192.168.6.51, port 5201
[ 5] local 192.168.6.133 port 35814 connected to 192.168.6.51 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 444 KBytes 3.64 Mbits/sec 0 26.9 KBytes
[ 5] 1.00-2.00 sec 311 KBytes 2.55 Mbits/sec 0 26.9 KBytes
[ 5] 2.00-3.00 sec 311 KBytes 2.55 Mbits/sec 0 26.9 KBytes
[ 5] 3.00-4.00 sec 373 KBytes 3.06 Mbits/sec 0 26.9 KBytes
[ 5] 4.00-5.00 sec 311 KBytes 2.55 Mbits/sec 0 26.9 KBytes
[ 5] 5.00-6.00 sec 373 KBytes 3.06 Mbits/sec 0 26.9 KBytes
[ 5] 6.00-7.00 sec 311 KBytes 2.55 Mbits/sec 0 26.9 KBytes
[ 5] 7.00-8.00 sec 373 KBytes 3.06 Mbits/sec 0 26.9 KBytes
[ 5] 8.00-9.00 sec 373 KBytes 3.06 Mbits/sec 0 26.9 KBytes
[ 5] 9.00-10.00 sec 311 KBytes 2.55 Mbits/sec 0 26.9 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 3.41 MBytes 2.86 Mbits/sec 0 sender
[ 5] 0.00-10.00 sec 3.30 MBytes 2.77 Mbits/sec receiver
