From owner-freebsd-current  Wed Aug 18  8:37:57 1999
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Date: Wed, 18 Aug 1999 08:36:39 -0700 (PDT)
From: Matthew Dillon <dillon@apollo.backplane.com>
Message-Id: <199908181536.IAA47581@apollo.backplane.com>
To: "Mark J. Taylor" <mtaylor@cybernet.com>
Cc: Sheldon Hearn <sheldonh@uunet.co.za>,
	Greg Lehey <grog@lemis.com>,
	Poul-Henning Kamp <phk@critter.freebsd.dk>, current@FreeBSD.ORG
Subject: Re: ccd bugs (was: Kernel hacker tasks seek interested hackers) 
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:We didn't go as far as modifying the structure definition, just the
:few "bcount" variables in the ccd.c code.
:The problem was that we were seeing bcount go "negative".  I believe that
:"newfs" of the ccd would panic the kernel, reliably.  Even on "smaller"
:ccds (1 Gbyte), I believe.
:I'm talking about ccds configured as in:
:  ccdconfig -c ccd0 0 0 /dev/da0s1c
:
:I know, this is fairly worthless as it stands, but it is done so we can
:later "upgrade" the ccd to a mirror.
:
:RSN, we will be moving to vinum.  Hi Greg!
:
:Linux, BTW, does s/w RAID5.  But, it seems you can't operate in degraded
:mode, and the RAID5 reconstruction happens at boot time.  We've got a 130
:GB RAID5 volume under Linux that takes about 10 hours to "ckraid".  I hope
:that this box never panics!
:
:-Mark Taylor
:NetMAX Developer
:mtaylor@cybernet.com
:http://www.netmax.com/

    This is very odd.  I use several multi-disk ccd stripes, including one at
    BEST across three 18G drives (one 54G partition!).  I've never had a 
    problem.

    I believe that at some point in the past 'newfs' and 'fsck' had overflow
    problems, but those were fixed.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>


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