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Date: Tue, 8 Jun 2004 07:30:13 GMT
From: JP Dinger <jpd@dsb.tudelft.nl>
To: freebsd-gnats-submit@FreeBSD.org
Subject: cvs update over a union mount slows and then slowly hangs the system
X-Send-Pr-Version: www-2.3

>Number:         67706
>Category:       kern
>Synopsis:       [unionfs] cvs update over a union mount slows and then slowly hangs the system
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    daichi
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jun 08 07:30:27 GMT 2004
>Closed-Date:    Tue Feb 13 06:03:08 GMT 2007
>Last-Modified:  Tue Feb 13 06:03:08 GMT 2007
>Originator:     JP Dinger
>Release:        4.9-REL-p9, 4.9-REL-p4, 4.10-REL
>Organization:
>Environment:
FreeBSD cazorp.gate5.de 4.9-RELEASE-p9 FreeBSD 4.9-RELEASE-p9 #1: Fri Jun  4 14:08:43 CEST 2004     root@cazorp.gate5.de:/usr/obj/usr/src/sys/PROZACII  i386

Also verified with GENERIC, of both 4.9-p4 and 4.10 (switched back from 4.10 to veryfy it wasn't a regression).
>Description:
With /usr/ports union mounted on /data/ports, cd /usr;cvs checkout ports 
will work but cvs update will make the machine unbearably slow, until no 
commands will work anymore. Symptoms include increasing slowness until
total halt, but switching vtys will keep working. Disc and network activity
will drop to zero as well, until interrupts/sec matches HZ. vmstat and top
(when they have been running before, starting them won't be doable) will
continue to update, however. The system will be 99.x% idle and run
0.(9-x)% sys, but no intr or user. Swap is not touched.
Namei and related cache stats are empty.

>How-To-Repeat:
df -h /data /usr
Filesystem    Size   Used  Avail Capacity  Mounted on
/dev/ad0s1h    87G   1.9G    78G     2%    /data
/dev/ad0s1f   1.2G   224M   872M    20%    /usr

mkdir /data/ports
mkdir /usr/ports

mount -t union /data/ports /usr/ports
cd /usr
cvs checkout ports
*optionally wait a day*
cvs update -dP ports

run systat -v or top and watch the machine do nothing. wait 15 minutes.
switch to another vty/login/whatever and try to start anything else.
Wait another 15 minutes, when the command hasn't even started decide the
machine is hung. Reboot, when the machine comes up umount the unionfsen
and try again directly in /data.
>Fix:
n/a
>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->suspended 
State-Changed-By: kris 
State-Changed-When: Fri Jun 11 07:46:02 GMT 2004 
State-Changed-Why:  
Suspended awaiting fix (unionfs is documented to be buggy). 

http://www.freebsd.org/cgi/query-pr.cgi?pr=67706 

From: David Schultz <das@FreeBSD.ORG>
To: JP Dinger <jpd@dsb.tudelft.nl>
Cc: freebsd-gnats-submit@FreeBSD.ORG
Subject: Re: kern/67706: cvs update over a union mount slows and then slowly hangs the system
Date: Wed, 22 Sep 2004 01:02:30 -0400

 On Tue, Jun 08, 2004, JP Dinger wrote:
 > mount -t union /data/ports /usr/ports
 > cd /usr
 > cvs checkout ports
 > *optionally wait a day*
 > cvs update -dP ports
 
 Do you mean a union mount (mount -o union) or a unionfs mount
 (mount -t unionfs)?  These are two different things.
Responsible-Changed-From-To: freebsd-bugs->daichi 
Responsible-Changed-By: rodrigc 
Responsible-Changed-When: Sun May 28 20:27:58 UTC 2006 
Responsible-Changed-Why:  
daichi is showing interest in unionfs 

http://www.freebsd.org/cgi/query-pr.cgi?pr=67706 
State-Changed-From-To: suspended->closed 
State-Changed-By: rodrigc 
State-Changed-When: Tue Feb 13 06:01:39 UTC 2007 
State-Changed-Why:  
New unionfs implementation has been committed to RELENG_6 and CURRENT. 
This bug report is only relevant to the previous version of unionfs. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=67706 
>Unformatted:
