Newish NFS mount option I missed until now: "nconnect="

[oshunluvr]

Source info here.

the "nconnect=" option lets you assign up to 16 TCP channels for NFS connections to presumably speed up transfer rates. I booted up this morning with the option enabled and it definitely seems quicker. I averaged roughly 10MB a sec. on a 1.1GB file move.

I haven't run a full set of comparison benchmarks yet, but thought it worth mentioning...

[Schwarzer Kater]

Please let us know the results of your comparison benchmarks - thanks!

[oshunluvr]

Initial testing results were not good.

TL/DR: Small (4K) files had little or no difference. Large file performance was noticeably worse.

My conclusion is either I have some other obstacle to NFS or network performance - like TCP/IP - or the nconnect option isn't doing what it was supposed to do.

Here's what I did.

Test setup:

• Created a folder with 1000x4K "zero" files in it
• Created a folder with 10x1GB "zero" files in it
• Both file systems are BTRFS
• The server is Ubuntu 20.04 using platter HDs
• The desktop is KDEneon using NVME drives

I ran all commands while logged out of the GUI and from the TTY console to avoid Dolphin or Plasma lag.

I copied each set of files from folder from my home NVME drive:
/test/small_out
/test/large_out

To folders residing on my server 12TB NAS drive:
/home/server/test/small
/home/server/test/large

Then copied them again the other direction:
/server/test/small >> /home/test/small_in
/server/test/large >> /home/test/large_in

The results are labeled as "OUT" meaning from /home to /server and "IN" meaning from /server to /home. I used a basic "cp" command with "time" command preceding it.

The results with nconnect=16 as a mount option:
Small files:

OUT
real 0m41.048s
user 0m0.017s
sys 0m0.391s

IN
real 0m0.281s
user 0m0.000s
sys 0m0.069s​​​

Large files:

OUT
real 2m6.916s
user 0m0.012s
sys 0m10.631s

IN
real 0m59.033s
user 0m0.005s
sys 0m8.714s

The results without nconnect=16 as a mount option:
Small files:

OUT
real 0m42.336s
user 0m0.020s
sys 0m0.342s

IN
real 0m0.826s
user 0m0.011s
sys 0m0.106s​​​

Large files:

OUT
real 1m50.887s
user 0m0.000s
sys 0m11.617s

IN
real 0m12.987s
user 0m0.005s
sys 0m4.889s​​

It's also very interesting to me that copying FROM the server happens faster than TO the server.