Re: software RAID 1 mirror details?

From: Alexander Dalloz (alexander.dalloz_at_uni-bielefeld.de)
Date: 05/20/04

  • Next message: Jack Howarth: "Re: software RAID 1 mirror details?" 
    Date: Thu, 20 May 2004 16:16:54 +0200
To: For users of Fedora Core releases <fedora-list@redhat.com>

    Am Do, den 20.05.2004 schrieb Jack Howarth um 15:41:

    > I have some questions regarding the proper way to
    > set up a software RAID 1 mirror under Fedora on two
    > identical SATA drives using the installation tools.
    > In particular I am seeking to create a complete
    > RAID 1 mirror so that if the main drive fails I can
    > simply move it out and reboot under the mirror.
    > What I am unclear on is how should I partition the
    > two drives and how these partitions are related
    > in the software RAID 1 mirror.

    http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/install-guide/s1-diskpartitioning.html

    Just create first the software RAID partitions you like with the size
    you prefer, as just a rough example /boot = 100MB on sda and sdb, / =
    4GB an both drives and swap = 512MB on both drives. Then in a second
    step create the RAID1 arrays from both drive's partitions. From my
    example choose the partitions you made for /boot on sda and sdb and set
    them as RAID1 array. Do that with the others too.

    > My first inclination is to use DiskDruid in the
    > installer to create identical sized partitions on
    > both SATA drives (three partitions each...
    > /boot, / and /swap). Of these I would only place the
    > partitions for /boot and / in the RAID. My rational
    > for this is that there is no point in mirroring the
    > /swap partition.

    If you really want to have swap as RAID1 mirror too, that is possible
    through Disk Druid.

    > Assuming this approach is correct, I am still
    > unclear on how the software RAID 1 mirror knows
    > which partitions on each drive to map to each other?

    The information is stored creating the RAID arrays. A map is to be found
    as /etc/raidtab, telling you which drive's partitions are building an
    array.

    > Does it just try to grossly map them by size and
    > do they have to be of identical size on both
    > drives of the RAID 1 or just bigger on ther mirror?
    > Thanks in advance for any clarifications.
    > Jack

    http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/custom-guide/ch-raid-intro.html

    Alexander 

    -- 
Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13
Fedora GNU/Linux Core 1 (Yarrow) on Athlon CPU kernel 2.4.22-1.2188.nptl
Sirendipity 16:09:28 up 7 days, 13:54, load average: 0.72, 0.42, 0.30 
                   [ Γνωθι σ'αυτον - gnothi seauton ]
             my life is a planetarium - and you are the stars



    


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  • Next message: Jack Howarth: "Re: software RAID 1 mirror details?"

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