Re: Configuring RAID 10 with RedHat ES 4 (64 bit)

From: Stephen Carville (stephen_at_totalflood.com)
Date: 05/18/05

  • Next message: Michael Schwendt: "Re: How to rebuild *.src.rpm in fedora 3"
    Date: Wed, 18 May 2005 06:13:58 -0700 (PDT)
    To: Andy Mountford <andrew.mountford@gmail.com>, General Red Hat Linux discussion list <redhat-list@redhat.com>
    
    

    On Wed, 18 May 2005, Andy Mountford wrote:

    > Hi,
    >
    > I am trying to configure an array of 12 disks in a RAID 10
    > configuration. All 12 disks are identical 146Gb drives.
    >
    > First off, on each disk I created a single partition which spanned the
    > whole disk with a system id of 0xFD. After writing the partition
    > table, a print confirmed all looked good.
    >
    > Secondly, I used mdadm to create 6 RAID 1 pairs. (mirrored).
    >
    > mdadm --create /dev/md0 --level=1 -n 2 /dev/sda /dev/sdb
    > mdadm --create /dev/md1 --level=1 -n 2 /dev/sdc /dev/sdd
    > mdadm --create /dev/md2 --level=1 -n 2 /dev/sde /dev/sdf
    > mdadm --create /dev/md3 --level=1 -n 2 /dev/sdg /dev/sdh
    > mdadm --create /dev/md4 --level=1 -n 2 /dev/sdi /dev/sdj
    > mdadm --create /dev/md5 --level=1 -n 2 /dev/sdk /dev/sdl
    >
    > cat /proc/mdstat showed the devices syncing. Once this had completed I
    > created a final meta device which striped the RAID1 meta devices. e.g.
    >
    > mdadm --create /dev/md6 --level 0 -n 6 /dev/md0 dev/md1 dev/md2
    > dev/md3 dev/md4 dev/md5
    >
    > I could then create a filesystem on the new array and mount it - all
    > looked good. However, 2 things concerned me:
    >
    > 1. After creating the RAID array, the partition table for all the
    > disks involved was empty and an fdisk returned:
    >
    > "Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)"
    >
    > What's going on here?
    >
    > 2. How can I get the array to come up after a reboot? What needs to be
    > done? Do I need an rc script that runs mdadm?

    I had a similar problem with an AS3 box that has a large RAID 0 I'd built
    using mdadm. Took me half a day to track it down.

    The rc.sysinit script for AS3 does not check for mdadm. It only looks for
    raidtab. so....

    Create an mdadm.conf file:

    $ echo 'DEVICE partitions' > mdadm.conf
    $ sudo mdadm --detail --scan --confin=mdadm.conf >>mdadm.conf
    $ sudo c p mdadm.conf /etc/mdadm.conf

    Add to rc.sysinit:

    if [ -f /etc/mdadm.conf ]; then
             /sbin/mdadm -A -s
    fi

    I added it right before the line that checks for /etc/raidtab but YMMV.

    --
    Stephen
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  • Next message: Michael Schwendt: "Re: How to rebuild *.src.rpm in fedora 3"

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