@george1421 said in Can you make FOG imaging go fast?:
I can say from my production FOG server running 2 vCPUs on a 24 core vSphere server, I can achieve about 6.2GB/min transfer rates (yes I know this number is a bit misleading since it also include decompression times, but its a relative number that we all can see) for a single unicast image.
That figure is not network transfer speed or compression/decompression speed nor is it an aggrigate, it is simply write speed to the host’s disk.
It doesn’t represent or reflect network transfer speed or decompression speeds. These things are very loosely related to the write speed just as the disk you’re using is related to the write speed - but this figure does not tell where any bottleneck is.
Trying to use this figure to gauge network transfer speed would be like trying to gauge the mail man’s speed based on how long it takes me to go check my mailbox (if the post office used that as their metric, the mailman would be fired because I check my mail every few days).
Further, your bottleneck is probably not the next person’s bottleneck. My experience with multiple FOG servers on multiple types of hardware has shown that tuning FOG is a matter of balancing network throughput with a host’s ability to decompress. We cannot speed up how fast a host’s disk can write, it’s maximum write speed is still it’s maximum write speed no matter what we do with CPU or Network or Compression or RAM - the idea is simply to always have data waiting to be written to disk without delay, and how to balance the CPU’s ability to decompress with the network’s ability to transmit to many clients at once, and the FOG server’s ability to serve many clients at once. This all comes back to two simple things I think: Max Clients and compression rate.
It’s a balancing act of these two things. Of course, ZSTD is the most superior compression algorithm, which is why it’s not one of the two simple things. But it’s compression rate is.
The FOG Server’s disk does play a role - but at my last job, I was clearly hitting the network’s maximum throughput bottleneck - so a solid state disk would not have helped.
At any rate, the script below is an example of how to automate the monitoring & collecting of things from FOS: https://github.com/FOGProject/fog-community-scripts/blob/master/fogAutomatedTesting/postinit.sh
That’s what I’d use to collect any custom metrics you want to monitor more quickly, instead of doing a debug every time and manually monitoring.
