From mboxrd@z Thu Jan  1 00:00:00 1970
From: Neil Brown <neilb@suse.de>
Subject: Re: RAID0 size bug (?)
Date: Sun, 10 Oct 2010 07:01:27 +1100
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Sender: linux-raid-owner@vger.kernel.org
To: Janos Haar <janos.haar@netcenter.hu>
Cc: linux-raid@vger.kernel.org
List-Id: linux-raid.ids

On Sat, 9 Oct 2010 21:09:16 +0200
"Janos Haar" <janos.haar@netcenter.hu> wrote:

> 
> ----- Original Message ----- 
> From: "Neil Brown" <neilb@suse.de>
> To: "Janos Haar" <janos.haar@netcenter.hu>
> Cc: <linux-raid@vger.kernel.org>
> Sent: Saturday, October 09, 2010 1:45 AM
> Subject: Re: RAID0 size bug (?)
> 
> 
> > On Sat, 9 Oct 2010 00:56:38 +0200
> > "Janos Haar" <janos.haar@netcenter.hu> wrote:
> >
> >> Hello list,
> >>
> >> Maybe a known old bug, but i don't know.
> >>
> >> The size is wrong of the md8:
> >>
> >> [root@UNISTORE ~]# fdisk -l /dev/sdh
> >>
> >> Disk /dev/sdh: 750.1 GB, 750156374016 bytes
> >                 ^^^^^^^^^
> >> 255 heads, 63 sectors/track, 91201 cylinders
> >> Units = cylinders of 16065 * 512 = 8225280 bytes
> >
> > So 750GB
> >
> >>
> >> Disk /dev/sdh doesn't contain a valid partition table
> >> [root@UNISTORE ~]# fdisk -l /dev/sdf
> >>
> >> Disk /dev/sdf: 500.1 GB, 500107862016 bytes
> >                 ^^^^^^^^^
> >> 255 heads, 63 sectors/track, 60801 cylinders
> >> Units = cylinders of 16065 * 512 = 8225280 bytes
> >
> > This one is 500GB
> >
> >
> >>
> >> Disk /dev/sdf doesn't contain a valid partition table
> >> [root@UNISTORE ~]# mdadm --detail /dev/md8
> >> /dev/md8:
> >>         Version : 00.90.03
> >>   Creation Time : Sat Oct  9 06:36:36 2010
> >>      Raid Level : raid0
> >>      Array Size : 1220961088 (1164.40 GiB 1250.26 GB)
> >                                            ^^^^^^^^^^^
> >
> > 750GB + 500GB == 1250 GB
> >
> > So what is your problem?
> 
> Shouldn't be 2x500GB?
> ...because this is stripe, not linear array. :-)
> 
> I mean should be used the smallest drive's size, no?

No.
Try
    man 4 md
and read the section in 'RAID0'.

NeilBrown


> 
> >
> > NeilBrown
> >
> >
> >>    Raid Devices : 2
> >>   Total Devices : 2
> >> Preferred Minor : 8
> >>     Persistence : Superblock is not persistent
> >>
> >>     Update Time : Sat Oct  9 06:36:36 2010
> >>           State : clean
> >>  Active Devices : 2
> >> Working Devices : 2
> >>  Failed Devices : 0
> >>   Spare Devices : 0
> >>
> >>      Chunk Size : 64K
> >>
> >>     Number   Major   Minor   RaidDevice State
> >>        0       8      112        0      active sync   /dev/sdh
> >>        1       8       80        1      active sync   /dev/sdf
> >> [root@UNISTORE ~]#
> >> [root@UNISTORE ~]# uname -a
> >> Linux UNISTORE 2.6.28.10 #5 SMP Fri Jan 29 07:40:35 CET 2010 x86_64 
> >> x86_64
> >> x86_64 GNU/Linux
> >> [root@UNISTORE ~]# mdadm -V
> >> mdadm - v2.5.4 - 13 October 2006
> >> [root@UNISTORE ~]#
> >>
> >>
> >> Cheers,
> >> Janos
> >>
> >> --
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