Linode Forum
Linode Community Forums
 FAQFAQ    SearchSearch    MembersMembers      Register Register 
 LoginLogin [ Anonymous ] 
Post new topic  Reply to topic
Author Message
 Post subject: tail -f delay
PostPosted: Fri Sep 30, 2011 8:14 pm 
Offline
Newbie

Joined: Fri Sep 30, 2011 8:02 pm
Posts: 2
I am experiencing long delays on tail -f command. I have read it may be to do with nfs. I am using the arch distro which does not have nfs userland tools installed but it shows nfsiod and rpciod in the kernel. I am not sure if this is what is causes the delay or if it is something else

Does anyone know how to disable the nfs in the kernel?

How does tail -f perform on other linodes?


Top
   
 Post subject: Re: tail -f delay
PostPosted: Fri Sep 30, 2011 8:50 pm 
Offline
Senior Member

Joined: Wed May 13, 2009 1:18 am
Posts: 681
iceman2 wrote:
I am experiencing long delays on tail -f command. I have read it may be to do with nfs. I am using the arch distro which does not have nfs userland tools installed but it shows nfsiod and rpciod in the kernel. I am not sure if this is what is causes the delay or if it is something else

I suspect whatever resource you looked at that mentioned nfs was referring to tailing a file that was mounted via nfs, since that can involve additional network latencies and potentially clock issues between the systems. Just having it in the kernel (or even mounting other filesystems) won't have any indirect impact on other filesystems.

Quote:
How does tail -f perform on other linodes?

Pretty normal in my experience. Tail'ing a file is always going to be subject to any latencies of data being written to the file, of course. Are you sure that the file you are watching is in fact getting written when you expect? You could be running into buffering/flushing issues with the process that is writing to the file - e.g., the delay could be on the write side rather than your tail's reading side.

-- David


Top
   
 Post subject:
PostPosted: Fri Sep 30, 2011 9:22 pm 
Offline
Newbie

Joined: Fri Sep 30, 2011 8:02 pm
Posts: 2
Now that you explain it like that it makes sense.

I will look further into the actual writing of the file


Top
   
 Post subject:
PostPosted: Fri Sep 30, 2011 10:42 pm 
Offline
Senior Member
User avatar

Joined: Tue Apr 13, 2004 6:54 pm
Posts: 833
If you see a large delay then lots of lines in a chunk then a large delay then a chunk of lines... this normally means the writing side is block buffered, rather than line buffered. In this case tail can't see any data 'cos nothing it's still in the buffer on the writing side.

_________________
Rgds
Stephen
(Linux user since kernel version 0.11)


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
RSS

Powered by phpBB® Forum Software © phpBB Group