Extremely slow NFS writes

deranjer · Jan 29th 2016

I have an NFS share mounted on my debian server. I was getting writing speeds in the KB/s range, so did some research and added async to the mount options, and now getting 16 MB/s write speeds, still way below acceptable. I then mounted my SMB share from openmediavault on my debian server and got 56MB/s speeds. Why are my NFS speeds so much lower than my SMB speeds? Also, don't understand how it says my NFS read speed is 8.2GB/s...

mount

Code

192.168.1.125:/RemoteStorage on /mnt/RemoteStorage type nfs4 (rw,relatime,sync,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=192.168.1.150,local_lock=none,addr=192.168.1.125)

fstab

Code

192.168.1.125:RemoteStorage /mnt/RemoteStorage nfs4 rw,sync,hard,intr 0 0

/etc/exports on server

Code

/export/RemoteStorage 192.168.1.0/24(rw,subtree_check,secure,async)

Code

root@pve:~# time dd if=/dev/zero of=/mnt/RemoteStorage/testfile bs=16k count=50000
50000+0 records in
50000+0 records out
819200000 bytes (819 MB) copied, 49.3278 s, 16.6 MB/s


real    0m49.974s
user    0m0.032s
sys     0m3.228s
root@pve:~# time dd if=/dev/zero of=/mnt/smbtest/testfile1 bs=16k count=50000
50000+0 records in
50000+0 records out
819200000 bytes (819 MB) copied, 14.5799 s, 56.2 MB/s


real    0m14.785s
user    0m0.000s
sys     0m0.816s
root@pve:~# time dd if=/mnt/RemoteStorage/testfile of=/dev/null bs=16k
50000+0 records in
50000+0 records out
819200000 bytes (819 MB) copied, 0.0996837 s, 8.2 GB/s


real    0m0.104s
user    0m0.000s
sys     0m0.096s
root@pve:~# time dd if=/mnt/smbtest/testfile1 of=/dev/null bs=16k
50000+0 records in
50000+0 records out
819200000 bytes (819 MB) copied, 9.5829 s, 85.5 MB/s


real    0m9.622s
user    0m0.008s
sys     0m0.192s

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deranjer · Jan 29th 2016

It would help if I didn't mount the nfs shares with "sync" when I specified "async" on the server. Removed the "sync" option and the nfs speed rose by a large amount.

avargas · Mar 4th 2021

Greetings,

Despite the fact that the solution is from more than 6 years ago, it served me too much. I had been with the failure for more than 15 days and could not find the solution.

My case is a server with OpenMediaVault with version 5.6.1-1 and I have a shared resource by NFS which transmitted before 100 MB / s to 250 MB / s and after the failure it went to 11 MB / s or less, but this was one moment after another that I stopped doing it, the only thing I remember doing before this error was running some updates (more than 30) that were available and then the failure began.

Configure the NFS, in the options of Services> NFS> Shared, the resource with:

rw, subtree_check, insecure, no_root_squash, async

Problem solved, Thanks and regards.

Extremely slow NFS writes

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