Slow network transfers with high IOWait times

[ironside]

Hello all. New Unraid user here. I finally convinced the misses to let me buy some hardware to make a proper server instead of using my kids windows pc as a storage server.

 

I have 2 4tb drives, an 8tb drive, and a 14tb drive, along with a 500gb nvme cache drive.

Specs: i5-11600k, 16gb ddr4 3200mhz, z590 mobo

 

 

I've been going through the process of transferring the data over, by emptying the 2 4tb drives onto the 14tb drive, and transplanting the 4tb drives into the NAS. Copying as much data over onto the now empty drives, so I can move the 8tb drive in as well. All that proceeded along swimmingly with zero issues. I though all was well.

 

Doing the exact same process with the 14TB drive is now causing me issues. The transfer will start fine at about 100MBPS, basically maxing out my gigabit network, but then will inevitably drop down to kilobytes. Sometimes it'll bounce around 11-15 MBPS but absolutely tanks the transfer rates as you can see below.

 

 

When looking at the dashboard CPU usage, you see cores spiking up to 100% which is not actually mirrored in the htop report in the terminal. Using netdata, it shows the culprit seems to be IOWait which spikes up at the same time as the drops in network transfer speeds as you can see in the screengrab below.

 

 

Here is a screengrab of my array setup:

 

 

I only have krusader and netdata installed as dockers currently.  As for plugins, I have Dynamix File Manager and Local Master, fix common problems, unassigned devices and devices plus, as well as user scripts

 

Any help would be greatly appreciated. If you need any more info, I will do my best to get it, but I'm quite new to all of this so I may need a nudge on where to get the info.

 

I've attached a diagnostics file from when the above iowaits were high.

ironsidenas-diagnostics-20221005-2207.zip

[JorgeB]

Disk3 is SMR, so it's normal to suffer lower write speeds every few minutes, does it get better if you temporarilly transfer just to the other disks?

[ironside]

It sometimes takes a while for the slowdown to get better, but you were right.  The SMR disk is really just INCREDIBLY slow and can't keep up with the writing.  I knew SMR was slower, but I didn't think it was THAT much slower.

 

I will have to avoid SMR like the plague in the future.