Slow write performance BTRFS FIX

[agppro]

Hi, I have unRAID 6.7.2 with this hardware

 

AMD Ryzen 7 2700

16 GB RAM

3 WD RED 4TB (one in parity) BTRFS

1 Seagate 2 TB (excluded from shared folder) BTRFS

All tunables in default

 

The problem is, when I copy a bunch of files from Windows 10 1909 to unraid shared folder on WD RED disks it goes perfectly at 112 MB/s, but when it finish to copy one file and starts the next one, it stops like 10 seconds and then continues at 112 MB/s. On the unRAID Dashboard I can see, sometimes one core is at 100%, but not allways

 

What can I do without adding cache to this problem dissapear?

 

Thanks

 

 

 

Edited December 8, 2019 by agppro

[Squid]

Sounds like filesystem overhead.  Especially noticeable if you're copying many small files concurrently.  Large files the net time difference isn't significant.

[agppro]

And what I can do for fix?

 

Thanks for your reply

[JorgeB]

Are you sure it's actually stopped? It happens to me sometime where explorer shows what appears to be a stalled transfer but Unraid writing continuasly, explorer is just not updating real time, you can check on the main page after toggling speed display or with the dynamix stats plugin.

[agppro]

It happens all the time, you can see the Windows 10 task manager statistics

[JorgeB]

That's not normal, post the diags, maybe something visible there. Also, is this using turbo write?

[agppro]

It fixed!

 

I read the turbo write post and I changed in Unraid -> Settings -> Disk Settings -> Tunable (md_write_method) from auto to reconstruct write

 

Now it fixed completely with small files, and with big files "like 6 GB" now it stops for half second; I understand Is calculating the parity and I think is now normal to the parity system of BTRFS

 

Thank you so much for your attention!