Softpedia
 


LINUX CATEGORIES:



GLOBAL PAGES >>
NEWS ARCHIVE >>
SOFTPEDIA REVIEWS >>
MEET THE EDITORS >>

WEEK'S BEST

  • BackTrack 5 R1
  • Wine 1.2.3 / 1.4 RC3
  • Mozilla Firefox 10...
  • Ubuntu 11.04
  • Angry Birds 1.1.2.1
  • Ubuntu 10.04.3 LTS
  • Linux Kernel 3.2.6
  • Ubuntu Manual 10.10
  • Adobe Flash Player...
  • Pidgin 2.10.1
  • Home > Linux > System > System Administration

    mdadm 3.2.2

    Download button

    No screenshots available
    Downloads: 6,642  View global page NEW!  Tell us about an update
    User Rating:
    Rated by:
    Fair (2.5/5)
    24 user(s)
    Developer:

    License / Price:

    Last Updated:

    Category:
    Neil Brown | More programs
    GPL / FREE
    June 17th, 2011, 08:41 GMT [view history]
    ROOT / System / System Administration

     Read user reviews (0)  Refer to a friend  Subscribe

    mdadm description

    A tool for creating, maintaining, and monitoring Linux

    mdadm project is a tool for maintaining, creating, and monitoring Linux "md" device arrays, also known as Software RAID.

    These notes apply to 2.6 kernels only and, in some cases, to 2.6.15 or later.

    Md arrays can be assembled at boot time using the 'autodetect' functionality
    which is triggered by storing components of an array in partitions of type
    'fd' - Linux Raid Autodetect.

    They can also be assembled by specifying the component devices in a
    kernel parameter such as

    md=0,/dev/sda,/dev/sdb

    In this case, /dev/md0 will be assembled (because of the 0) from the listed
    devices.

    These mechanisms, while useful, do not provide complete functionality
    and are unlikely to be extended. The preferred way to assemble md arrays at boot time is using 'mdadm' or 'mdassemble' (which is a trimmed-down mdadm).

    To assemble an array which contains the root filesystem, mdadm needs to be run before that filesystem is mounted, and so needs to be run from an initial-ram-fs. It is how this can work that is the primary focus of this document.

    It should be noted up front that only the array containing the root
    filesystem should be assembled from the initramfs. Any other arrays
    should be assembled under the control of files on the main filesystem
    as this enhanced flexibility and maintainability.

    A minimal initramfs for assembling md arrays can be created using 3 files and one directory. These are:

    /bin Directory
    /bin/mdadm statically linked mdadm binary
    /bin/busybox statically linked busybox binary
    /bin/sh hard link to /bin/busybox
    /init a shell script which call mdadm appropriately.


    An example init script is:

    #!/bin/sh

    echo 'Auto-assembling boot md array'
    mkdir /proc
    mount -t proc proc /proc
    if [ -n "$rootuuid" ]
    then arg=--uuid=$rootuuid
    elif [ -n "$mdminor" ]
    then arg=--super-minor=$mdminor
    else arg=--super-minor=0
    fi
    echo "Using $arg"
    mdadm -Acpartitions $arg --auto=part /dev/mda
    cd /
    mount /dev/mda1 /root || mount /dev/mda /root
    umount /proc
    cd /root
    exec chroot . /sbin/init < /dev/console > /dev/console 2>&1



    Product's homepage

    What's New in This Release: [ read full changelog ]

    · Firstly there is the "policy" framework. This allows us to set policy for different devices based on where they are connected (e.g. which controller) so that e.g. when a device is hot-plugged it can immediately be made a hot-spare for an array without further operator intervention. It also allows broader controller of spare-migration between arrays. It is likely that more functionality will be added to this framework over time
    · Secondly, the support for Intel Matrix Storage Manager (IMSM) arrays has been substantially enhanced. Spare migration is now possible as is level migration and OLCE (OnLine Capacity Expansion). This support is not quite complete yet and requires MDADM_EXPERIMENTAL=1 in the environment to ensure people only use it with care. In particular if you start a reshape in Linux and then shutdown and boot into Window, the Windows driver may not correctly restart the reshape. And vice-versa.

      


    TAGS:

    monitoring md device | creating md device | maintaining md device | mdadm | monitoring | creating



    HTML code for linking to this page:


    Go to top

    WindowsGamesDriversMacLinuxScriptsMobileHandheldNews

    SUBMIT PROGRAM   |   ADVERTISE   |   GET HELP   |   SEND US FEEDBACK   |   RSS FEEDS   |   UPDATE YOUR SOFTWARE   |   ROMANIAN FORUM