From dillon@backplane.com  Thu Oct 16 17:31:18 1997
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Date: Thu, 16 Oct 1997 17:31:08 -0700 (PDT)
From: Matthew Dillon <dillon@backplane.com>
Reply-To: dillon@backplane.com
To: FreeBSD-gnats-submit@freebsd.org
Subject: manual page for dump incorrect
X-Send-Pr-Version: 3.2

>Number:         4785
>Category:       docs
>Synopsis:       incorrect explanaion in manual page for dump
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:
>Keywords:
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Oct 16 17:40:01 PDT 1997
>Closed-Date:    Sun Oct 19 11:45:09 MEST 1997
>Last-Modified:  Sun Oct 19 11:45:28 MEST 1997
>Originator:     Matthew Dillon
>Release:        FreeBSD 2.2-STABLE i386
>Organization:
Best Internet
>Environment:


>Description:

	The manual page for dump, for the 0-9 options, specifies:

     -0-9    Dump levels.  A level 0, full backup, guarantees the entire file
             system is copied (but see also the -h option below).  A level
             number above 0, incremental backup, tells dump to copy all files
             new or modified since the last dump of the same or lower level.
             The default level is 9.

	It says "last dump of the SAME or lower level".   As best as I can
	determine, dump's actual mechanism is to copy all files new or
	modified since the last dump of a lower level.  Not the same level.

>How-To-Repeat:

	dump 0ubf 64 - / > /dev/null
	dd if=/dev/zero of=/xxx bs=32k count=10		(create big file)
	dump 1ubf 64 - / > /dev/null
	dump 1ubf 64 - / > /dev/null
	dump 1ubf 64 - / > /dev/null
	...

	note that the second and third level 1 dumps are the same size as
	the first level 1 dump.

>Fix:
	
	The documentation needs to be fixed.  I don't think the program is
	broken.

>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: joerg 
State-Changed-When: Sat Oct 18 15:21:43 MEST 1997 
State-Changed-Why:  

The desription in the manual page is arguably a little confusingly 
worded, but entirely correct. 

From: j@uriah.heep.sax.de (J Wunsch)
To: dillon@backplane.com
Cc: FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: docs/4785: manual page for dump incorrect
Date: Sat, 18 Oct 1997 15:22:58 +0200

 As Matthew Dillon wrote:
 
 > 	It says "last dump of the SAME or lower level".   As best as I can
 > 	determine, dump's actual mechanism is to copy all files new or
 > 	modified since the last dump of a lower level.  Not the same level.
 
 Nope, the same level.  You can repeatedly dump at the same level (!=
 0), and will get just the increments since the last run.
 
 > >How-To-Repeat:
 > 
 > 	dump 0ubf 64 - / > /dev/null
 > 	dd if=/dev/zero of=/xxx bs=32k count=10		(create big file)
 > 	dump 1ubf 64 - / > /dev/null
 > 	dump 1ubf 64 - / > /dev/null
 > 	dump 1ubf 64 - / > /dev/null
 > 	...
 > 
 > 	note that the second and third level 1 dumps are the same size as
 > 	the first level 1 dump.
 
 Usage error.  If you modify it like this:
 
 	dump 0ubf 64 - / > /dev/null
 	dump 1ubf 64 - / > /dev/null
 	dd if=/dev/zero of=/xxx bs=32k count=10		(create big file)
 	dump 1ubf 64 - / > /dev/null
 	dump 1ubf 64 - / > /dev/null
 
 ...the first level 1 dump won't dump anything (since nothing has
 changed since the last level 0 dump), but the second level 1 dump will
 dump the new file.  The third level 1 dump, again, has nothing to dump
 since nothing has changed.
 
 -- 
 cheers, J"org
 
 joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
 Never trust an operating system you don't have sources for. ;-)

From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
To: j@uriah.heep.sax.de (J Wunsch)
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: docs/4785: manual page for dump incorrect
Date: Sat, 18 Oct 1997 12:11:47 -0400 (EDT)

 <<On Sat, 18 Oct 1997 07:00:01 -0700 (PDT), j@uriah.heep.sax.de (J Wunsch) said:
 
 >  As Matthew Dillon wrote:
  
 >> It says "last dump of the SAME or lower level".   As best as I can
 >> determine, dump's actual mechanism is to copy all files new or
 >> modified since the last dump of a lower level.  Not the same level.
  
 >  Nope, the same level.  You can repeatedly dump at the same level (!=
 >  0), and will get just the increments since the last run.
  
 If true, this is totally broken with respect to the way dump has
 historically worked.  The mechanism described by Dillon is the way
 dump is supposed to work, and if either the program or the
 documentation disagrees, it should be fixed.  Many people's backup
 strategies depend on the correct behavior.
 
 -GAWollman
 
 --
 Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
 wollman@lcs.mit.edu  | O Siem / The fires of freedom 
 Opinions not those of| Dance in the burning flame
 MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick

From: j@uriah.heep.sax.de (J Wunsch)
To: wollman@khavrinen.lcs.mit.edu (Garrett Wollman)
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: docs/4785: manual page for dump incorrect
Date: Sat, 18 Oct 1997 19:19:23 +0200

 As Garrett Wollman wrote:
 
 > If true, this is totally broken with respect to the way dump has
 > historically worked.  The mechanism described by Dillon is the way
 > dump is supposed to work, and if either the program or the
 > documentation disagrees, it should be fixed.
 
 After careful re-checking, it seems you are right on this.
 
 -- 
 cheers, J"org
 
 joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
 Never trust an operating system you don't have sources for. ;-)

From: Matthew Dillon <dillon@backplane.com>
To: j@uriah.heep.sax.de (J Wunsch)
Cc: FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: docs/4785: manual page for dump incorrect
Date: Sat, 18 Oct 1997 11:15:33 -0700 (PDT)

 :Usage error.  If you modify it like this:
 :
 :	dump 0ubf 64 - / > /dev/null
 :	dump 1ubf 64 - / > /dev/null
 :	dd if=/dev/zero of=/xxx bs=32k count=10		(create big file)
 :	dump 1ubf 64 - / > /dev/null
 :	dump 1ubf 64 - / > /dev/null
 :
 :...the first level 1 dump won't dump anything (since nothing has
 :changed since the last level 0 dump), but the second level 1 dump will
 :dump the new file.  The third level 1 dump, again, has nothing to dump
 :since nothing has changed.
 
     J"org, I'm pretty sure the third level 1 dump saves /xxx again. 
 
 apollo:/home/dillon#  dump 0ubf 64 - / > /dev/null
   DUMP: Date of this level 0 dump: Sat Oct 18 11:12:54 1997
   DUMP: Date of last level 0 dump: the epoch
   DUMP: Dumping /dev/rsd0a (/) to standard output
   DUMP: mapping (Pass I) [regular files]
   DUMP: mapping (Pass II) [directories]
   DUMP: estimated 17950 tape blocks.
   DUMP: dumping (Pass III) [directories]
   DUMP: dumping (Pass IV) [regular files]
   DUMP: DUMP: 18023 tape blocks
   DUMP: finished in 13 seconds, throughput 1386 KBytes/sec
   DUMP: level 0 dump on Sat Oct 18 11:12:54 1997
   DUMP: DUMP IS DONE
 apollo:/home/dillon#  dump 1ubf 64 - / > /dev/null
   DUMP: Date of this level 1 dump: Sat Oct 18 11:13:08 1997
   DUMP: Date of last level 0 dump: Sat Oct 18 11:12:54 1997
   DUMP: Dumping /dev/rsd0a (/) to standard output
   DUMP: mapping (Pass I) [regular files]
   DUMP: mapping (Pass II) [directories]
   DUMP: estimated 45 tape blocks.
   DUMP: dumping (Pass III) [directories]
   DUMP: dumping (Pass IV) [regular files]
   DUMP: DUMP: 100 tape blocks
   DUMP: finished in less than a second
   DUMP: level 1 dump on Sat Oct 18 11:13:08 1997
   DUMP: DUMP IS DONE
 apollo:/home/dillon# dd if=/dev/zero of=/xxx bs=32k count=10 
 10+0 records in
 10+0 records out
 327680 bytes transferred in 0.022121 secs (14813025 bytes/sec)
 apollo:/home/dillon# dump 1ubf 64 - / > /dev/null
   DUMP: Date of this level 1 dump: Sat Oct 18 11:13:19 1997
   DUMP: Date of last level 0 dump: Sat Oct 18 11:12:54 1997
   DUMP: Dumping /dev/rsd0a (/) to standard output
   DUMP: mapping (Pass I) [regular files]
   DUMP: mapping (Pass II) [directories]
   DUMP: estimated 369 tape blocks.
   DUMP: dumping (Pass III) [directories]
   DUMP: dumping (Pass IV) [regular files]
   DUMP: DUMP: 422 tape blocks
   DUMP: finished in 1 seconds, throughput 422 KBytes/sec
   DUMP: level 1 dump on Sat Oct 18 11:13:19 1997
   DUMP: DUMP IS DONE
 apollo:/home/dillon#  dump 1ubf 64 - / > /tmp/yy
   DUMP: Date of this level 1 dump: Sat Oct 18 11:13:24 1997
   DUMP: Date of last level 0 dump: Sat Oct 18 11:12:54 1997
   DUMP: Dumping /dev/rsd0a (/) to standard output
   DUMP: mapping (Pass I) [regular files]
   DUMP: mapping (Pass II) [directories]
   DUMP: estimated 369 tape blocks.
   DUMP: dumping (Pass III) [directories]
   DUMP: dumping (Pass IV) [regular files]
   DUMP: DUMP: 422 tape blocks
   DUMP: finished in 1 seconds, throughput 422 KBytes/sec
   DUMP: level 1 dump on Sat Oct 18 11:13:24 1997
   DUMP: DUMP IS DONE
 apollo:/home/dillon# 
 
 apollo:/home/dillon# restore tvbf 64 - < /tmp/yy
 Verify tape and initialize maps
 Dump   date: Sat Oct 18 11:14:31 1997
 Dumped from: Sat Oct 18 11:12:54 1997
 Level 1 dump of / on apollo.backplane.com:/dev/sd0a
 Label: none
 Extract directories from tape
 Initialize symbol table.
 dir          2  .
 dir          3  ./dev
 leaf       292  ./dev/null
 leaf       491  ./dev/ttyp2
 leaf       497  ./dev/ttyp5
 leaf       503  ./dev/ttyp8
 leaf       504  ./dev/ptyp8
 leaf       505  ./dev/ttyp9
 leaf       506  ./dev/ptyp9
 dir        184  ./etc
 leaf       677  ./etc/dumpdates
 leaf       119  ./xxx
 
 
 :-- 
 :cheers, J"org
 :
 :joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
 :Never trust an operating system you don't have sources for. ;-)
 :
 
     Matthew Dillon   Engineering, BEST Internet Communications, Inc.
 		     <dillon@apollo.backplane.com>
     [always include a portion of the original email in any response!]
State-Changed-From-To: closed->open 
State-Changed-By: joerg 
State-Changed-When: Sun Oct 19 11:44:46 MEST 1997 
State-Changed-Why:  

Matt was right... 
State-Changed-From-To: open->closed 
State-Changed-By: joerg 
State-Changed-When: Sun Oct 19 11:45:09 MEST 1997 
State-Changed-Why:  

...and it has been fixed in rev 1.18 of dump.8. 
>Unformatted:
