Slightly OT: local network bandwidth - upload vs. download

Hi,

In my local network I have a sandbox PC, a battered Dell Optiplex 3020 with a core i5 processor and 8 GB RAM that I’m using to test all the stuff that requires bare metal and can’t be tested in a VM (KVM, Proxmox, etc.) The sandbox PC sports a small 60 GB SSD disk.

Besides this I have an equally battered Synology NAS running an FTP server for the local net. This NAS has a single purpose: host various Ghost images from the sandbox machine.

Let’s say there’s a custom Rocky Linux 8 install on the sandbox PC. Once I’ve done all my testing, I want to backup this installation. Usually I’m running the following command within the system to zero out everything on the disk that is not the installation itself:

# dd if=/dev/zero of=/0bits bs=20M ; rm -f /0bits

Once this is done, I boot G4L (Ghost4Linux) and transfer the contents of the sandbox PC to the FTP server on the NAS, bit by bit in a filesystem-agnostic raw mode. I’ve done this for years and it really is a no-brainer.

On my NAS I have a series of images, each a handful of gigabytes in size:

  • rocky-8-srvbase
  • rocky-9-srvbase
  • rocky-8-desktop
  • rocky-9-desktop
  • windows-10
  • proxmox
  • etc.

This setup has been working perfectly for more than a decade now. Except there’s one detail that’s nagging me.

When I boot up Ghost4Linux on the sandbox PC and backup my Ghost image to the NAS, uploading all this is relatively fast. Displayed bandwidth is around 150 MB/sec. Whole process takes around 5 minutes.

On the other hand, when I want to fetch a Ghost image from the NAS and install it to the sandbox PC, downloading the Ghost image is painfully slow, somewhere around 10 to 20 MB/sec. Whole process takes about an hour to complete.

I’m not a network expert, so I’m a bit clueless here. Any idea if there is something to be done here to improve download speed?

Cheers,

Niki

Have you checked your small SSD on your sandbox PC? Is it worn out? I suspect if it was worn out after many years of usage.
To test out, you may install smartmontools, and test your drive with smartctl

sudo yum install smartmontools
smartctl -t long /dev/sda
smartctl -a /dev/sda
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