WD White label drives get 30% faster when running Short Smart check?!?

[TexasUnraid]

TL:DR

Was doing unraid pre-clear when smart short test started, speed jumped from ~200MB/s to 250MB/s+

Later was doing parity sync when smart short tests were started on all drives and speed on all drives once again jumped from ~190-200MB/s to 250-260MB/s

When one smart test failed and stopped early, that drive speed once again dropped down to ~200MB/s slowing the rest of course.

More testing needs to be done but this is very interesting and very annoying that we get the extra heat, noise, wear and tear of 7200rpm drives but not the speed.

Picture proof at bottom

I would love to see others test this as well to get a wider understanding of what we are seeing.

 

Ok, I have not seen this reported yet and it was a shocker to me but I think I finally narrowed down the anomaly.

This started when I was pre-clearing a new 14TB EDFZ (also tested on 12TB EMFZ)drive from Black Friday. Was getting the normal ~200MB/s speeds at the start and the average over the first leg was like all my other shucked "5400rpm" drives.

 

Edit: Someone else replicated the results on reddit as well with the WD80EMAZ

 

Then all the sudden I get up the next morning and notice it made way more progress then I expected overnight. I go back though the netdata logs and notice that the speed spiked all the sudden from ~200MB/s up to ~250MB/s and stayed there until the end of the cycle. It then went back to normal speeds for the rest of the post-read.

 

I was perplexed indeed, I knew at this point it was actually a 7200rpm drive but I could not figure out what made it actually give 7200rpm speeds.

 

Fast forward a few days and I am replacing my parity drive with said 14TB EDFZ drive. I start the parity sync with my array of all EMFZ 12TB drives and everything is normal, ~200MB/s. Leave it for a bit and when I come back I notice that out of nowhere ALL the drives are reading/writing at 250MB/s??

 

Naturally I start to investigate, I quickly realize that all the drives say they are in the process of running a short smart test and it all clicks. I have a script setup to run a short smart test every night on all the drives in my system and save the smart report for future tracing of any issues.

 

The drives sped up exactly when the SMART test script ran and the SMART short test seemed to hang at 90% due to the parity check so the speeds just stayed fast seemingly until it was finished based on the prior 14TB pre-clear.

 

It seems to confirm that the drives are 7200rpm drives that are firmware locked to keep them to ~200MB/s speeds.

 

I did further testing during a pre-clear and sure enough the results are repeatable. Pre-clearing another drive the average speed went from ~160MB/s to 209MB/s average.

 

Some pictures of the speed change:

 

 

Combines speed change of all drives

Before smart test single drive speeds

After Smart test single drive speed

Edited December 5, 2020 by TexasUnraid

[trurl]

50 minutes ago, TexasUnraid said:

cross post this here

where else did you post this?

[TexasUnraid]

8 minutes ago, trurl said:

where else did you post this?

I guess it is not technically a cross post since it was not on this site.

Edited December 5, 2020 by TexasUnraid