Bug 115292

Summary: Poor NFS performance with netapp filer
Product: Red Hat Enterprise Linux 3 Reporter: Peter Schauer <schauer>
Component: kernelAssignee: Steve Dickson <steved>
Status: CLOSED WONTFIX QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 3.0CC: dhoward, petrides, riel
Target Milestone: ---   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-10-19 19:30:16 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Description Peter Schauer 2004-02-10 10:53:34 UTC
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Description of problem:
This is a IBM eserver 325, running RHEL 3 AMD64, connected to a netapp
filer. The eserver is connected via a 100MB link to a switch, which is
connected via a GB FC to the netapp.

We are using autofs with NIS to mount directories from the filer.

RHEL 3 seems to default to use a rsize/wsize of 32768 with UDP with
the netapp,
which results in very poor performance with many nfsstat -c retrans

Using TCP or a rsize/wsize of 4096 fixes the performance problems, but
we cannot change the autofs maps as we are running in a heterogenous
environment, where we cannot force these parameters for other hosts on
the network (some can't do TCP, for many a rsize/wsize of 4096 is
contraproductive, and the options syntax is different for Linux and

Currently we work around the problem by using a local file copy of the
auto.master map which we hack to use TCP, but this is not a long term
Older versions of RedHat kernels (9, 8.0 etc.) and SuSe SLES 8.1 kernels
limited the default UPD rsize/wsize to 4096, so they didn't cause the

Possible fixes:
- Default to use TCP mounts when the NFS server supports them.
- Limit UDP rsize/wsize defaults to 4096 like in older RedHat kernels.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1.Copy file from/to netapp with default mount parameters.

Actual Results:  Very slow

Additional info:

Comment 1 Don Howard 2004-03-01 23:01:06 UTC
Can you post nfsstat output and a pcap-format packet capture 
(including nfs fragments) that demonstrates the retransmit behavior? 

Comment 2 RHEL Product and Program Management 2007-10-19 19:30:16 UTC
This bug is filed against RHEL 3, which is in maintenance phase.
During the maintenance phase, only security errata and select mission
critical bug fixes will be released for enterprise products. Since
this bug does not meet that criteria, it is now being closed.
For more information of the RHEL errata support policy, please visit:
If you feel this bug is indeed mission critical, please contact your
support representative. You may be asked to provide detailed
information on how this bug is affecting you.