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Hello all, hopefully this find you all well.... I have a cool project that I am undertaking and I wanted to know if anyone else has undergown something similar. So ...
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  1. #1
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    RHEL 6 live san migration


    Hello all, hopefully this find you all well.... I have a cool project that I am undertaking and I wanted to know if anyone else has undergown something similar. So here we go I have a RHEL 6 instance on a physical machine and for hardware failure concerns we dont use local disk.. That being said we use san for all storage. Well now the san we are on is EOL and we have to move all systems off. Have anyone done a live migration from one san to another while the system was online?

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    Are you upgrading to the same brand of SAN so they have management software to split the writes to two SANs?

    I've worked on migrations but usually part of moving from one brand SAN to another so we just had to switch to read-only data and take and outage to switch over. So our app's were up just no updating till migration was over. For migration servers we used VM machines, migrated the physical machine to a virtual, decommissioned the old hardware, built the new then migrated the VM over to the new machine, then short outage to switch to new physical machine.

    Be interested in hearing how you do this once done.
    A lion does not lose sleep, over the opinion of sheep.

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    So this is what I have in mine ofcourse vanilla and off the top of my head......
    New /boot - grub install and all that good stuff on new boot partition
    LVM new disk
    pvcreate /dev/disk (LVM) ofcourse
    vgexted /dev/old /dev/new
    pvmove --v /dev/old /dev/new

    done what you think?

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    Quote Originally Posted by terrywhitejr2000 View Post
    So this is what I have in mine ofcourse vanilla and off the top of my head......
    New /boot - grub install and all that good stuff on new boot partition
    LVM new disk
    pvcreate /dev/disk (LVM) ofcourse
    vgexted /dev/old /dev/new
    pvmove --v /dev/old /dev/new

    done what you think?
    Should be fine, as long as you don't have an insane amount of IOPS during the migration. At this point RHEL+LVM2 is pretty rock solid. Make sure you have good (read tested) backups before you try it.

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    So....... thought if I do a pvmove I shouldnt have to create a new boot or anything right? Shouldnt it work like so?
    new lvm vg created 70G old one is 70G
    pvmove /dev/old /dev/new ? remove old disk should be fine?

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    Quote Originally Posted by terrywhitejr2000 View Post
    So....... thought if I do a pvmove I shouldnt have to create a new boot or anything right? Shouldnt it work like so?
    new lvm vg created 70G old one is 70G
    pvmove /dev/old /dev/new ? remove old disk should be fine?
    /boot isn't generally on a LV, so that shouldn't be a concern.
    After you migrate the data, you'll want to remove the partitions from the VG before removing disks.

    http://www.tldp.org/HOWTO/LVM-HOWTO/...pvsfromvg.html

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    So after thinking i found that my sugestion was stupid right /boot what was I thinking... so this is what I am thinking new 500Mb/boot out of new disk (old disk are going away and we dont use local disk so will need a new /boot). create some new pv's import the vg's into the existing vg... then for each pv in the vg im going to do a pvmove /dev/old to /dev/new.....
    Last edited by terrywhitejr2000; 05-22-2014 at 01:36 AM. Reason: add more details

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    So yeah I saw that doc and a few others trying to see if anyone else has done it and how they accomplished this.... I will let you all know how it goes once I finish and document the steps I took as I have not found to many post on how to move from one san array to another so I am looking forward to doing it.

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