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Date:	Fri, 11 Feb 2000 12:03:59 +0100 (CET)
From:	Ingo Molnar <mingo@chiara.csoma.elte.hu>
To:	Frank Davis <fdavis112@juno.com>
Subject: new RAID subsystem in 2.3.43 [was: Re: 2.3.44pre2 missing


FYI:

the new RAID code is being merged into 2.3. As of 2.3.43, the block-IO
queueing extensions, the new RAID ioctl interface and new RAID-superblock
code and most generic RAID facilities are already merged, along with the
new linear and RAID0 personality. RAID1/RAID4,5 are not supposed to work,
or even compile - work is underway to merge those as well.

RAID0 (and linear) had a data corruption bug on SMP since around 2.3.18,
this bug got fixed as well. 'access beyond end of device ..' type of
crashes under heavy multiple-interface IO load were the most typical form
of this bug.

BIG FAT WARNING: the 2.3 RAID code is not yet considered to be 'stable'
yet, all the usual disclaimers wrt. development kernels apply. It does
happen to work for me, but it might eat your data. You have been warned.

To use new-style RAID first make sure to have read the RAID-HOWTO:

	http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/

and the latest stable 0.90 raidtools is needed as well:

	http://www.kernel.org/pub/linux/daemons/raid/alpha/raidtools-19990824-0.90.tar.bz2

(all and any historical superblock-less RAID installations and older
superblock layouts are supported without data loss.)


On Fri, 11 Feb 2000, Frank Davis wrote:

>        As stated in previous kernel releases...(2.3.43pre8), there is a
> missing drivers/block/xor.c needed to compile RAID ('make dep'
> make[4]errror). Does anyone know  where that file went? 

i cannot see a single reference to xor.c in any 2.3.4x kernel tree. xor.c
is part of the new RAID5 code which is not yet merged. Could there be a
mixup of patches?

-- mingo


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