CentOS 7 Cannot Reach Network Bandwidth 10GB

[khemarith]

i have install CentOS 7 for running my application.
i have add network 10GB CentOS with Adapter Type : VMXNET 3.
i have install vmware tools ready for this CentOS 7.
my problem with try to download and upload file from CentOS 7 network speed reach only 150mbs - 200mbs.
i try reinstall CentOS many time but still network speed reach only 150mbs - 200mbs.

[shiva_jr]

Hi Khemarith,
   This is not at all concerned with the server, VM OS. It is purely depends on the network fabric speed, Switch configuration, Network configuration in Virtual machine, size of upload or download data etc.
Try this -
1) Source and destination network ports for download and upload can be connected to single switch.
2) NICs must run in full duplex mode.
3) If possible, enable the jumbo frames.
4) Check the virtual machine resource is suffecient.
5) Verify the switch speed, its load and other dependants. Set the switch for complete utiliization of its speed.
Regards,
Shiva_JR

[khemarith]

@shiva_jr 

Dear Thank you for your reply

1) Source and destination network ports for download and upload can be connected to single switch. (Source and destination for download and upload is on single switch)
2) NICs must run in full duplex mode. (NICs is run in full duplex mode ready.)
3) If possible, enable the jumbo frames. (MTU size i have change to 9000 bytes)
4) Check the virtual machine resource is suffecient. (virtual machine resource is fine)
5) Verify the switch speed, its load and other dependants. Set the switch for complete utiliization of its speed. (switch speed is fine i have test ready.)

More infor

i have try install Windows Server 2019 on this NICs and try copy data for test speed can reach 10GB. 

[Vinky_99]

@khemarith 

Good day

If you have a 10GB network adapter but are only getting speeds of 150-200Mbps, there are several factors that could be contributing to this issue. Here are some steps to troubleshoot and potentially improve your network speed:

* Verify that the virtual network adapter is indeed set to 10GB in the VMware configuration for the virtual machine.
* Ensure that the physical network infrastructure, including the switch and network cables, supports 10GB speeds.
* Make sure that VMware Tools is properly installed and up to date. VMware Tools can help improve the performance of the virtual machine.
* You can use the ethtool command to check the negotiated network speed of your network interface. Run the following command:

ethtool eth0

- Replace 'eth0' with the name of your network interface. Look for the "Speed" line to confirm the negotiated speed. It should be 10Gbps.

* Ensure that your virtual machine is using a hardware version that supports 10GB network adapters. You can check and update this in the VM settings.
* Check the CentOS 7 settings for the network adapter. You can modify the network configuration in
'/etc/sysconfig/network-scripts/ifcfg-eth0' (or the appropriate network interface configuration file) to ensure it's set to the correct speed and that it's not being limited.

* Ensure that the driver for the VMXNET 3 network adapter is up to date. Sometimes, outdated drivers can limit network performance.
* Check for firmware updates for your physical hardware, including the server and network adapter.
* High network latency or network congestion can impact your network speeds. Check if there are any latency issues on your network.
* Ensure that there is no other heavy network traffic on the same network segment or switch that could be affecting your VM's performance.
* You can try tuning the network stack in CentOS for better performance. This may involve adjusting parameters like the Maximum Transmission Unit (MTU) and network buffer sizes. However, be cautious when making such changes, as they can have unintended consequences.

* Check if any firewall or security software running on the CentOS VM is limiting network performance.
* Ensure that the host system (the physical server running VMware) has enough resources to support the desired network speed. CPU, RAM, and disk performance can also impact network speed.
* In VMware, you can also adjust the virtual machine's resource allocation settings, including CPU and memory, to ensure it has enough resources to handle the 10GB network speed.
* In VMware, you can also adjust the virtual machine's resource allocation settings, including CPU and memory, to ensure it has enough resources to handle the 10GB network speed.

If after checking these factors you still experience slow network speeds, it may be necessary to engage with your network and virtualization administrators or consult VMware and CentOS support resources for further assistance.

I hope this helps! Let me know ...