Re: RAID0 size bug (?)

"Janos Haar" <janos.haar@xxxxxxxxxxxx> · Sat, 9 Oct 2010 21:09:16 +0200

----- Original Message ----- 
From: "Neil Brown" <neilb@xxxxxxx>
To: "Janos Haar" <janos.haar@xxxxxxxxxxxx>
Cc: <linux-raid@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxx> 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?

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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