The following reply was made to PR kern/29540; it has been noted by GNATS.

From: Greg Oster <oster@cs.usask.ca>
To: gnats-bugs@netbsd.org, netbsd-bugs@netbsd.org
Cc: riz@tastylime.net
Subject: Re: kern/29540: raidframe can show clean parity on raid1 with a failed disk 
Date: Sun, 27 Feb 2005 00:01:46 -0600

 riz@tastylime.net writes:
 > >Number:         29540
 > >Category:       kern
 > >Synopsis:       raidctl can show clean parity on raid1 with failed disk
 [snip]
 > Components:
 >           component0: failed
 >            /dev/wd0a: optimal
 [snip]
 > >How-To-Repeat:
 > 
 > 	Build a raid1 set, calculate parity.  Then, relabel one disk,
 > removing the raid partition, and newfs it.  Reboot normally, and
 > see that parity is 'clean'.
 > 
 > >Fix:
 > 	Unknown - this is probably straightforward, and one could
 > possibly argue that the behavior is "correct" - but it's certainly
 > surprising.
 
 The behaviour is correct.  The parity status is not dependent on 
 whether or not there is any parity present.  Another way to think 
 about "clean" is "if you end up having to read parity bits, and there 
 are parity bits, then they are known to be good".  "Dirty" means 
 "we havn't verified the parity to be good, and if you need to re
 construct something from that parity, you're on your own."  
 
 What the "clean" status tells you in your case is that when the RAID
 set went into degraded mode, the parity bits were in sync with the
 data bits (in RAID 1 land, that both components had the same data).  
 If it had said "dirty" instead, then that would have meant that the 
 system didn't know for sure if /dev/wd0a was in sync with component0, 
 and there possibly could be data loss (since component1 is basically 
 the "parity" for component0 in the case of a RAID 1 set).
 
 Perhaps an explanation of this for the man-page might be in order, 
 but the behaviour is correct..
 
 Later...
 
 Greg Oster