NFS: new data takes long time to sync

[mosh]

Hi,
Since moving to NFS, i encountered a very interesting (and frustrating) case
I have a FreeNAS server NFS v3 mount on two clients, a client is writing a file to the NFS datastore. the other client is trying to read the file after 750ms and it is failing with 'file not found' error

Any idea what could be the cause for this issue?

Server: FreeNAS-11.1-U4
clients: Ubuntu 14.04

Thanks,
Moshe

 

[Chris Moore]

There is a lot involved in the potential answer here that you have not shared. Something as simple as how large the file is or what kind of network, 1Gb or 10Gb, could make a massive difference.

How about some details?

For some ideas on what to share, you could look to this article:
https://forums.freenas.org/index.php?threads/updated-forum-rules-8-3-16.45124/

 

[Chris Moore]

750ms

PS. That is not even one whole second. Is it a super tiny file? Maybe you just need a bit more time.

 

[rvassar]

That almost sounds like the client is caching the negative. Are you using any obtuse mount options? Have you tried "sync,lookupcache=none"? I remember hearing some of the Linux NFS clients get tripped up on directory caching when there's a ctime update without the mtime getting bumped.

Are any of these clients VM's? Make sure your NTP isn't wobbling.

 

[mosh]

There is a lot involved in the potential answer here that you have not shared. Something as simple as how large the file is or what kind of network, 1Gb or 10Gb, could make a massive difference.

How about some details?

For some ideas on what to share, you could look to this article:
https://forums.freenas.org/index.php?threads/updated-forum-rules-8-3-16.45124/

Hi,
I'm using 10Gb network and the file being read is very small

 

[mosh]

That almost sounds like the client is caching the negative. Are you using any obtuse mount options? Have you tried "sync,lookupcache=none"? I remember hearing some of the Linux NFS clients get tripped up on directory caching when there's a ctime update without the mtime getting bumped.

Are any of these clients VM's? Make sure your NTP isn't wobbling.

Hi,
These are physical clients, NTP is working well i have that under monitoring.
I can try adding those parameters you suggested. those goes to the client side config, right?

 

[rvassar]

Client side mount options, yes.