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Old 04-20-2012, 06:29 PM
Helmut Jarausch
 
Default NFS terribly slow on writes

Hi,

on one of our students' lab the home directories of the students are
mounted via NFS.
Our main application (www.codelite.org) seems to write a lot of small
chunks to files in the

students' home directories.

Thus, just finishing Codelite takes 100 seconds while the same version
on a pure local machine

takes about 2 seconds for that.

A simple test
dd bs=80 count=10000 if=/dev/zero of=$HOME/Test
shows only 80 Kb/sec (speed of a floppy drive).
The machine was idle and connected to a dedicated, nearly idle server
by a network

of 1Gb/sec.

Does anybody have some hints on how to speed up such an NFS3 setup?

Many thanks for some clues.

By the way, NFS was set up with the async option.

Helmut.
 
Old 04-20-2012, 08:28 PM
Robert David
 
Default NFS terribly slow on writes

Hi Helmut,

this is common problem with nfs. I would suggest investigate more about
nfs4 (better caching). And try to play with mount options
rsize=1024,wsize=1024. I think default is 8k.

Robert.


V Fri, 20 Apr 2012 20:29:57 +0200
Helmut Jarausch <jarausch@igpm.rwth-aachen.de> napsáno:

> Hi,
>
> on one of our students' lab the home directories of the students are
> mounted via NFS.
> Our main application (www.codelite.org) seems to write a lot of
> small chunks to files in the
> students' home directories.
>
> Thus, just finishing Codelite takes 100 seconds while the same
> version on a pure local machine
> takes about 2 seconds for that.
>
> A simple test
> dd bs=80 count=10000 if=/dev/zero of=$HOME/Test
> shows only 80 Kb/sec (speed of a floppy drive).
> The machine was idle and connected to a dedicated, nearly idle
> server by a network
> of 1Gb/sec.
>
> Does anybody have some hints on how to speed up such an NFS3 setup?
>
> Many thanks for some clues.
>
> By the way, NFS was set up with the async option.
>
> Helmut.
>
 
Old 04-20-2012, 08:34 PM
Michael Mol
 
Default NFS terribly slow on writes

On Fri, Apr 20, 2012 at 2:29 PM, Helmut Jarausch
<jarausch@igpm.rwth-aachen.de> wrote:
> Hi,
>
> on one of our students' lab the home directories of the students are mounted
> via NFS.
> Our main application (www.codelite.org) seems to write a lot of small chunks
> to files in the
> students' home directories.
>
> Thus, just finishing Codelite takes 100 seconds while the same version on a
> pure local machine
> takes about 2 seconds for that.
>
> A simple test
> dd bs=80 count=10000 if=/dev/zero of=$HOME/Test
> shows only 80 Kb/sec (speed of a floppy drive).
> The machine was idle and connected to a dedicated, nearly idle server by a
> network
> of 1Gb/sec.
>
> Does anybody have some hints on how to speed up such an NFS3 setup?

There's all kinds of NFS tuning options. I'm not an expert, so I can't
really make any strong suggestions, but my first stop would probably
be grabbing the ebook version of
http://shop.oreilly.com/product/9781565925106.do and giving that a
good couple hours' deep skim.


--
:wq
 
Old 04-20-2012, 09:04 PM
Matthew Marlowe
 
Default NFS terribly slow on writes

the biggest things to think about:
- nfs versions (some work better or are more compatible with others)
- nfs write/read cache settings
- use nfsstat to get an idea of what the nfs traffic is like
- is filesystem constantly having locking issues or refreshing file
attributes? might need to change mount options.
- if not local lan, might have significant problems...especially with mtu
- doesn't hurt to check iostat -x -k 5 on sending server too along
with nic card stats
- it usually isn't that hard to track down where the problem lies
- I've had great performance with nfs over local lans, horrible issues
with any kind of remote nfs....newer nfs versions are trying to work
around the issues.

On Fri, Apr 20, 2012 at 1:34 PM, Michael Mol <mikemol@gmail.com> wrote:
> On Fri, Apr 20, 2012 at 2:29 PM, Helmut Jarausch
> <jarausch@igpm.rwth-aachen.de> wrote:
>> Hi,
>>
>> on one of our students' lab the home directories of the students are mounted
>> via NFS.
>> Our main application (www.codelite.org) seems to write a lot of small chunks
>> to files in the
>> students' home directories.
>>
>> Thus, just finishing Codelite takes 100 seconds while the same version on a
>> pure local machine
>> takes about 2 seconds for that.
>>
>> A simple test
>> dd bs=80 count=10000 if=/dev/zero of=$HOME/Test
>> shows only 80 Kb/sec (speed of a floppy drive).
>> The machine was idle and connected to a dedicated, nearly idle server by a
>> network
>> of 1Gb/sec.
>>
>> Does anybody have some hints on how to speed up such an NFS3 setup?
>
> There's all kinds of NFS tuning options. I'm not an expert, so I can't
> really make any strong suggestions, but my first stop would probably
> be grabbing the ebook version of
> http://shop.oreilly.com/product/9781565925106.do and giving that a
> good couple hours' deep skim.
>
>
> --
> :wq
>



--
Matthew Marlowe
matt@professionalsysadmin.com
https://www.twitter.com/deploylinux
1-805-857-9144
 

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