LinuxQuestions.org - 4x2TB drives in software RAID5 in Debian Lenny

Hi,

I'm about to hang myself... :-(

My goal is the following:

Software RAID 5 on 4 2TB caviar green disks. Then 12 partitions or about 500GB, and finally LVM to use the partitions as pv, and create some vg for my needs.

My disks are /dev/sda to /dev/sdd
I boot on /dev/sde which is an sd card

My doing (and at the end, my issue):

Code:

(parted) select /dev/sda

(parted) mklabel

Warning: The existing .... blablabla [msdos] ? gpt

(parted) select /dev/sdb

(parted) mklabel

Warning: The existing .... blablabla [msdos] ? gpt

(parted) select /dev/sdc

(parted) mklabel

Warning: The existing .... blablabla [msdos] ? gpt

(parted) select /dev/sdd

(parted) mklabel

Warning: The existing .... blablabla [msdos] ? gpt

quit

Then:

Code:

mdadm --create /dev/md0 --verbose --chunk=256 --level=5 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd

resulted in

Code:

mdadm: layout defaults to left-symmetric

mdadm: /dev/sda appears to be part of a raid array:

    level=raid5 devices=4 ctime=Sun May  2 04:59:56 2010

mdadm: /dev/sdb appears to be part of a raid array:

    level=raid5 devices=4 ctime=Sun May  2 04:59:56 2010

mdadm: /dev/sdc appears to be part of a raid array:

    level=raid5 devices=4 ctime=Sun May  2 04:59:56 2010

mdadm: /dev/sdd appears to be part of a raid array:

    level=raid5 devices=4 ctime=Sun May  2 04:59:56 2010

mdadm: size set to 1953514496K

Continue creating array? y

mdadm: array /dev/md0 started.

Here, I'm not sure why it set the size to 2TB. I thought it was the parity size... is it ?

anyhow, mdadm --detail /dev/md0 returns:

Code:

/dev/md0:

        Version : 00.90

  Creation Time : Sun May  2 13:32:02 2010

    Raid Level : raid5

    Array Size : 5860543488 (5589.05 GiB 6001.20 GB)

  Used Dev Size : 1953514496 (1863.02 GiB 2000.40 GB)

  Raid Devices : 4

  Total Devices : 4

Preferred Minor : 0

    Persistence : Superblock is persistent



    Update Time : Sun May  2 13:33:27 2010

          State : clean, degraded, recovering

 Active Devices : 3

Working Devices : 4

 Failed Devices : 0

  Spare Devices : 1



        Layout : left-symmetric

    Chunk Size : 256K



 Rebuild Status : 0% complete



          UUID : ec3fbf51:f7d0b544:16911994:d274d6b7 (local to host caprica)

        Events : 0.6



    Number  Major  Minor  RaidDevice State

      0      8        0        0      active sync  /dev/sda

      1      8      16        1      active sync  /dev/sdb

      2      8      32        2      active sync  /dev/sdc

      4      8      48        3      spare rebuilding  /dev/sdd

Seems correct to me so fare.

Therefore, I try now to partition /dev/md0:

1st thing's 1st, when I go into parted /dev/md0 I get the following question:

Code:

GNU Parted 1.8.8

Using /dev/md0

Welcome to GNU Parted! Type 'help' to view a list of commands.

(parted) p

Error: The backup GPT table is not at the end of the disk, as it should be.  This might

mean that another operating system believes the disk is smaller.  Fix, by moving the

backup to the end (and removing the old backup)?

Fix/Cancel?

I type Fix and then I have the following:

Code:

Warning: Not all of the space available to /dev/md0 appears to be used, you can fix the

GPT to use all of the space (an extra 7814057808 blocks) or continue with the current

setting?

Fix/Ignore?

Therefore... Fix again...

Now a print gives me:

Code:

Model: Unknown (unknown)

Disk /dev/md0: 6001GB

Sector size (logical/physical): 512B/512B

Partition Table: gpt



Number  Start  End  Size  File system  Name  Flags

Doesn't looks bad... Then comes the problems:

Code:

mkpart part1 0 500GB

result:

Code:

Error: Error informing the kernel about modifications to partition /dev/md0p1 -- Invalid

argument.  This means Linux won't know about any changes you made to /dev/md0p1 until you

reboot -- so you shouldn't mount it or use it in any way before rebooting.

Ignore/Cancel?

I can go on with Ignore or Cancel, whatever. I can create all the partitions I want. It will gives this message for each partition everytime I make a parted command on the volume. Then, after reboot, there is no device node for the created partitions.

For the example, I just made one. After reboot, cat /proc/partitions returns:

Code:

 cat /proc/partitions

major minor  #blocks  name



  8    0 1953514584 sda

  8    16 1953514584 sdb

  8    32 1953514584 sdc

  8    48 1953514584 sdd

  9    0 5860543488 md0

  8    64  15986688 sde

  8    65  15269751 sde1

  8    66          1 sde2

  8    69    714861 sde5

What the hell :-( What did I miss ...