Bug 139355 - Documentation for 'rsize' and 'wsize' NFS mount options is misleading
Documentation for 'rsize' and 'wsize' NFS mount options is misleading
Status: CLOSED ERRATA
Product: Red Hat Enterprise Linux 3
Classification: Red Hat
Component: util-linux (Show other bugs)
3.0
i686 Linux
medium Severity medium
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Assigned To: Steve Dickson
Brian Brock
RHEL3U7NAK
: FutureFeature
Depends On:
Blocks: 148897 170110 RHEL3U8CanFix
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Reported: 2004-11-15 10:17 EST by Daniel Berrange
Modified: 2007-11-30 17:07 EST (History)
3 users (show)

See Also:
Fixed In Version: RHBA-2006-0456
Doc Type: Enhancement
Doc Text:
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Clone Of:
Environment:
Last Closed: 2006-07-20 10:45:12 EDT
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CRM:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


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Description Daniel Berrange 2004-11-15 10:17:27 EST
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4)
Gecko/20030624 Netscape/7.1 (ax)

Description of problem:
In the section detailing mount options for NFS filesystems, it says
that the default value for rsize and wsize options is 4k.

[quote]
   rsize=8192,wsize=8192
      This  will make your nfs connection faster than with the default
      buffer size of 4096. (NFSv2 does not work with larger values  of
      rsize and wsize.)
[/quote]

This does not tie up with what the kernel source appears to be doing,
which is to use the server specified default values. The performance
turning pages at http://nfs.sourceforge.net/nfs-howto/performance.html
also say that the default is typically server specified.

[quote]
  If no rsize and wsize options are specified, the default varies by
  which version of NFS we are using. The most common default is 4K
  (4096 bytes), although for TCP-based mounts in 2.2 kernels, and
  for all mounts beginning with 2.4 kernels, the server specifies
  the default block size.
[/quote]


Version-Release number of selected component (if applicable):
mount-2.11y-31.1

How reproducible:
Always

Steps to Reproduce:
1. man 'mount'
2. Search for 'rsize'/'wsize'
3.
    

Expected Results:  Documentation for default value of rsize/wsize
options corresponds to actual practice in kernel source.

Additional info:
The man page should probably also warn about potential problems with
an oversized rsize/wsize as the the above doc on nfs.sourceforge.net

[quote]
If the rsize/wsize  is too large the symptoms are very odd and not
100% obvious. A typical symptom is incomplete file lists when doing
ls, and no error messages, or reading files failing mysteriously
with no error messages.
[/quote]
Comment 1 Don Buchholz 2005-01-11 12:43:30 EST
Also, the mount(8) and nfs(5) man pages have conflicting statements
about the default rsize,wsize values.  Mount(8) says 4K; nfs(5) says 1K.
Comment 2 Steve Dickson 2005-10-07 09:12:53 EDT
Fixed in util-linux-2.11y-31.12
Comment 12 Bob Johnson 2006-04-11 12:00:16 EDT
This issue is on Red Hat Engineering's list of planned work items 
for the upcoming Red Hat Enterprise Linux 3.8 release.  Engineering 
resources have been assigned and barring unforeseen circumstances, Red 
Hat intends to include this item in the 3.8 release.
Comment 16 Red Hat Bugzilla 2006-07-20 10:45:13 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2006-0456.html

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