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Hello, I am in the process of setting up a master/slave server that's running redhat 9. The partition setup is as follows: hda / /home /boot # boots from MBR ...
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  1. #1
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    setting boot 1st from Master, second from slave


    Hello,
    I am in the process of setting up a master/slave server that's running redhat 9. The partition setup is as follows:

    hda
    /
    /home
    /boot # boots from MBR
    swap

    hdb
    /
    /home
    /boot # boots from boot partition
    swap

    I am setting up a cron to daily clone hda to hdb using the dd if=/dev/hda of=/dev/hdb method.

    I would like to set the boot loader to automatically boot from master and then the slave if the master hd fails.

    Would Grub be the best way of doing this if it's doable in the first place?

    Thanx,
    Clem

  2. #2
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    you can "fallback" to a different entry in /etc/grub.conf

    add:

    Code:
    fallback 1
    to grub.conf (Note: 0 is the first entry 1 is the second)

    http://www.faqs.org/docs/Linux-mini/...RUB.html#ss2.7

  3. #3
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    Great - thanx for pointing me in this direction. I'm actually simulating a raid1 setup to save drive space so I hope this will all work out.

    I'm assuming the dd copy method will clone the slave perfectly to run it in case of an emergency

    Thanks aganin,

    The Clem

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  5. #4
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    Why dd? Wouldn't it be better to set up the disks in a software RAID 1 array, so that they are always perfectly mirrored? That way you won't have the risk of the machine crashing in the middle of a dd and thus ruining your mirroring as well.

  6. #5
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    yeah - I know the raid is the optimal setup except for the fact that it cuts your disk size in half. We have 2 80 g hardrives and 1 of our sites could easily grow to 20 g's in a years time. I'm trying to set this up so we don't have to spend anymore money on 2 160 g drives.

    -Clem

  7. #6
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    Oh no, RAID1 doesn't cut it in half at all. It just mirrors the content on two (or more) hard drives. That is, if you have two 80 GB drives, you get one 80 GB RAID array.

    I think what you might be confusing it with is that if you have two 80 GB drives, that is 160 GB total, you'll get half the total, that is 80 GB, to use.

  8. #7
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    I guess I'm a bit cofused about raid1. Everything I read about it says it's drawback is it cuts your disk size in half which means I would only have 40 g of space on both drives if I was using 2 80 g drives.

    -Clem C

  9. #8
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    No, that's false. What they mean when they say "cut in half" is that with two 80 GB hard drives, you have 160 GB, but when you raid them, you will get a 80 GB RAID device, cutting that total space in half.

    The plain and simple truth is this: The RAID device will be as large as the smallest hard drive in the array.

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