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Date: Tue, 8 May 2007 19:30:03 GMT
From: Seraphi<seraphi.lord@gmail.com>
To: freebsd-gnats-submit@FreeBSD.org
Subject: NFS over TCP under load hangs with "impossible packet length"
X-Send-Pr-Version: www-3.0

>Number:         112529
>Category:       amd64
>Synopsis:       NFS over TCP under load hangs with "impossible packet length"
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-amd64
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue May 08 19:40:04 GMT 2007
>Closed-Date:    Tue May 08 21:12:20 GMT 2007
>Last-Modified:  Tue May 08 21:12:20 GMT 2007
>Originator:     Seraphi
>Release:        6.2-RELEASE-p4
>Organization:
>Environment:
FreeBSD nfsclient05.domain.com 6.2-RELEASE-p4 FreeBSD 6.2-RELEASE-p4 #0: Tue May  8 13:59:19 EDT 2007     admin@nfsclient05.domain.com:/usr/obj/usr/src/sys/MYKERN_62_05042007  amd64
>Description:
NFS over UDP will hang under load and throw the following errors to syslog:
May  8 14:36:55 nfsclient05 kernel: impossible packet length (13050202) from nfs server 192.168.101.12:/store22
May  8 14:36:56 nfsclient05 kernel: impossible packet length (1669907873) from nfs server 192.168.101.12:/store22
May  8 14:37:01 nfsclient05 kernel: impossible packet length (46381) from nfs server 192.168.101.12:/store22

I have tried many mount options, but here is one set that will have this problem:
192.168.101.12:/store22       /s22           nfs     ro,-i,-b,-3,-T,-r=16384,-w=16384 0 0

To get the error to occur, I simply copy a multi-gig file from NFS to a local drive. It happens very frequently.  I have only tried this on gigabit networks.

The error goes away if I use UDP, which is what I am using until this is fixed.

I have tried this on FreeBSD 6.1 as well and had the same problem. I have also tried a different NFS server running a different OS on a different network with a different configuration on different hardware. It did not help. I have tried updating with freebsd-update but the status is unchanged.

>How-To-Repeat:
Put an NFS client and server on a gigabit network. Mount the server using TCP:
192.168.101.12:/store22       /s22           nfs     ro,-i,-b,-3,-T,-r=16384,-w=16384 0 0

Copy a large file (1GB+) from the NFS mount to a local drive. Do this a couple of times, then check /var/log/messages
>Fix:
Use UDP:
192.168.101.12:/store22       /s22           nfs     ro,-i,-b,-3,-U,-r=16384,-w=16384 0 0
>Release-Note:
>Audit-Trail:

From: Seraphi <seraphi.lord@gmail.com>
To: bug-followup@FreeBSD.org
Cc:  
Subject: Re: amd64/112529: NFS over TCP under load hangs with "impossible packet length"
Date: Tue, 8 May 2007 16:02:56 -0400

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 This is a duplicate of 112528. This can be removed.
 
 On 5/8/07, FreeBSD-gnats-submit@freebsd.org <
 FreeBSD-gnats-submit@freebsd.org> wrote:
 >
 > Thank you very much for your problem report.
 > It has the internal identification `amd64/112529'.
 > The individual assigned to look at your
 > report is: freebsd-amd64.
 >
 > You can access the state of your problem report at any time
 > via this link:
 >
 > http://www.freebsd.org/cgi/query-pr.cgi?pr=112529
 >
 > >Category:       amd64
 > >Responsible:    freebsd-amd64
 > >Synopsis:       NFS over TCP under load hangs with "impossible packet
 > length"
 > >Arrival-Date:   Tue May 08 19:40:04 GMT 2007
 >
 
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 This is a duplicate of 112528. This can be removed.<br><br>
 <div><span class="gmail_quote">On 5/8/07, <b class="gmail_sendername"><a href="mailto:FreeBSD-gnats-submit@freebsd.org">FreeBSD-gnats-submit@freebsd.org</a></b> &lt;<a href="mailto:FreeBSD-gnats-submit@freebsd.org">FreeBSD-gnats-submit@freebsd.org
 </a>&gt; wrote:</span>
 <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Thank you very much for your problem report.<br>It has the internal identification `amd64/112529&#39;.<br>
 The individual assigned to look at your<br>report is: freebsd-amd64.<br><br>You can access the state of your problem report at any time<br>via this link:<br><br><a href="http://www.freebsd.org/cgi/query-pr.cgi?pr=112529">
 http://www.freebsd.org/cgi/query-pr.cgi?pr=112529</a><br><br>&gt;Category:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; amd64<br>&gt;Responsible:&nbsp;&nbsp;&nbsp;&nbsp;freebsd-amd64<br>&gt;Synopsis:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; NFS over TCP under load hangs with &quot;impossible packet length&quot;<br>
 &gt;Arrival-Date:&nbsp;&nbsp; Tue May 08 19:40:04 GMT 2007<br></blockquote></div><br>
 
 ------=_Part_99612_6233867.1178654576430--
State-Changed-From-To: open->closed 
State-Changed-By: jmg 
State-Changed-When: Tue May 8 21:11:48 UTC 2007 
State-Changed-Why:  
dup of 112528 per submitter 

http://www.freebsd.org/cgi/query-pr.cgi?pr=112529 
>Unformatted:
