Slow write speed to cache drive (40MB/s)

[Waddle]

Hi,

I have slow write speeds to cache disk (around 40MB/s)

Scenario:
Docker hosting Sonarr/Radarr copying files from M.2 disk on a PC to separate Unraid server

Copying to Unraid SSD in share (https://www.amazon.co.uk/gp/product/B09XDJ673F) 

Mostly 10gbps capable network but capped by 2.5gbps NIC on the Sonarr PC. 
Network tested with iperf confirming 2gbps+ speeds between machines

Unraid SSD tested with DiskSpeed - showing 200MB/s 
M.2 tested with Ubuntu benchmark - showing 3000MB/s+

The SSD had previously been filled so I trimmed and this appeared to help (network was showing ~2.5gbps inbound traffic immediately after trim) but it quickly degraded again. Subsequent trims haven't really helped

 

Has anyone experienced similar? Appreciate any suggestions!

beamish-nas-diagnostics-20220926-1537.zip

[JorgeB]

Enable turbo write and copy directly to the array, that will help test if it's a cache device problem.

[Waddle]

Writing directly to the array it is fluctuating 100-200MB/s, maxing out 2.5gbps inbound traffic

 

[JorgeB]

That suggest the SSD you are using is just slower, suggest getting one known to perform better, like the Samsung 870 EVO or Crucial MX500 for example.

[Waddle]

Thank you

 

May as well get an M.2 ready for the 10gbps network in that case

 

Is it fine to use an M.2 with a PCI-E adapter?
 

Are there any recommended M.2 models for Unraid?

[Waddle]

Never mind, I've ran out of PCI slots 

Ordered a Crucial MX500 as advised

Will report back once that's confirmed to fix the issue 

[Waddle]

Just to confirm, the Crucial SSD is working as expected

Significantly faster write speeds from the second machine to the NAS with cache mode activated

 

Thanks again @JorgeB, I really appreciate your help!

[ytddewqf]

Just found a post from @tbonedude420 which may explain my issue. If this is the case would the introduction of a further "faster" drive, as part of the array be possible? That way downloads are made direct to NVME, but then when copying to the array for permanent storage (and currently bringing the system to a halt, potentially because my mechanical array HDD's can't keep up) I could have them copied to a faster SSD or something similar as a kind of bridge. I don't know if this is even possible, but at this point I'm open to any solution to remedy this issue.

 

Edited October 8, 2022 by BeardedNoir