Transfer starts good then stalls

[Joris]

Hello,

 

I just started testing my Unraid build and am having a problem with the transfer of files from a Qnap NAS to my new Unraid server.

 

I mounted a nfs share with Unassigned Devices and started a transfer with Kursader. When the transfer begins, the speed is maxed out at around 1000Mbps because of the LAN connection. All goes well for about 20-30GiB after that it usually drops to a few hundred KiB/s of simply stalls.

 

After a bit of fiddling, i changed the Disk Cache 'vm.dirty_background_ratio' (%): to 10% and Disk Cache 'vm.dirty_ratio' (%): to 4% 

 

This seemed to fix the issue (was able to transfer 400GiB) until I started a preclear on an unmounted hard drive connected via a HBA card. Then the speed then dropped to a few hundred KiB/s/stalled. 

 

Edit : After it stalls, it I cancel the copy and start a new instance, it copies back at around 1000Mbps. 

 

For the moment, I'm not using any parity disks and the issue happens with a xfs and an encrypted xfs file system.

 

I also tied TurboWrite but it didn't have any noticeable difference. 

 

Any idea on what to try that could help would be great.

 

My build is currently like this:

• Motherboard : Gigabyte X570 Aorus Master
• CPU : AMD Ryzen 7 3800X
• 4 hard drives connected to MoBo
• 4 hard drives connected to LSI SAS9305-16i 
• all hard drives are 8Tb WD Red
• 2x 16GiB of Corsair Vengeance LPX, DDR4

 

Edited May 11, 2021 by Joris
New information

[Joris]

I captured a transfer event that stalled with netdata. 

 

That data was being written to the sdg disk when the stall happend.

netdata-JBAS-NAS-20210512-071038-304.snapshot

[JorgeB]

First try an SMB transfer from a computer to see if it's the same, if yes grab the diagnostics after the stall and post them here.