write speed slows down (6MB/s) after few minutes, no cache, no parity, restarting unraid fixes it for a while

[062bel313]

Hello all:

 

First of all, I would like apologize if the issue has been already answered. I spent hours in the forum and couldn't find solution for my case.

 

I just built an UNRAID server and am currently trying to copy all the media I have in my Synology to UNRAID. Both are in same LAN network.

 

My system spec:

AMD Ryzen 7 3700x

Gigabit LAN

One 16TB Exos enterprise drive

One m2 and 16TB Exos drive as unassigned drive. I am planning to use exos as parity drive later and m2 is already used as appdata for my emby.

 

I do not have cache or parity drive at the moment.

 

My Issue:

When copying the files from Synology to UNRAID, using Krusader docker, at first the copy process starts from around ~110MB/s then drops down to 6MB/s after few minutes (around 10 minutes). However the throughput of Synology is still around 120MB/s, I have tested it locally from my PC. Also, If I write to UNRAID from windows during that time it writes at ~6MB/s.

I also tested it using a SABnzbd (docker in UNRAID) to download the files in UNRAID, and it downloads at the speed of 7MB/s. I am guessing the write speed is limiting the WAN bandwidth.

 

Now, If I restart the UNRAID, the download form SABnzbd resumes to 30MB/s (my max WAN down speed) and the write speed in Krusader or windows shows around 110MB/s for few minutes (around 10-15 minutes) then again drops down to 6MB/s.

 

I am not able to figure out the issue. Can anyone please help! ?

 

I have attached the diagnostics.

syslog.txt

Thank you,

062bel313.

 

 

[itimpi]

I did not spit anything obvious in the syslog you posted.    However that is NOT the diagnostics that are a zip file obtained via Tools >> Diagnostics which contain a lot more about your system (and includes the syslog as part of the information).

 

The description of an initial fast burst and the speed then dropping suggests that at first the data is being buffered in RAM, and then once that has filled the speed drops.    No idea why this is happening for you

[062bel313]

Hi itimpi,

 

Sorry, didn't realize I posted the incomplete information. Attached is the complete diagnostics.

 

Regarding the RAM, I can see my RAM is only 6% utilized (out of 32GB). Did a test when RAM was less utilized and same ~6MB/s speed.

 

Thank you,

062bel313

merounraid-diagnostics-20200521-0043.zip

[062bel313]

Not sure what SABnzbd docker is doing on the background, but it was the culprit. I was previously using binhex and now I am running linuxserver with same settings and things are good now. Hopefully it will stay like this.