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  • 1.  copy lv from one vg to another with dd?

    Posted Tue May 25, 2010 07:40 AM

    Originally posted by: j.gann


    Hi all,

    I need to move a large jfs2 filesystem with millions of small files from one vg to another.
    short timeframe (app downtime).
    I suspect cp -r/cpio/rsync to be very slow.

    cplv copies 1 PP (64MB source in my case, target flexible) at a time, makes me more happy ;-) but my favourite would be dd with a large (G?) blocksize of the underlying lv (fs unmounted of course). Is this even possible?

    any caveats?

    thanks for yr feedback
    Joachim


  • 2.  Re: copy lv from one vg to another with dd?

    Posted Tue May 25, 2010 11:15 AM

    Originally posted by: hdkutz


    Hello,
    use
    1. cplv
    which lets you copy your lv from one VG to another.
    Short Example:
    <snip>
    cplv -y'<new Name>' -v<VG> <old_Name>
    cplv -y'application04LV' -v'application01VG' application02LV
    <snip>
    More Params in the man-Page.

    Cheers,
    ku


  • 3.  Re: copy lv from one vg to another with dd?

    Posted Tue May 25, 2010 11:33 AM

    Originally posted by: hdkutz


    Sorry,
    over looked your statement to cplv.
    Maybe this link helps:
    http://www.keyongtech.com/4433368-dd-from-jfs2-to-raw
    Someone using dd to copy from jfs2 to raw.

    Cheers,
    ku


  • 4.  Re: copy lv from one vg to another with dd?

    Posted Wed May 26, 2010 11:51 PM

    Originally posted by: j.gann


    thanks for the input. I ran a test now and found dd using large amounts of memory (much more than the buffer size). Even though it is using no fs cache in my raw lv case.
    cplv also provided more throughput. worked fine. cplv to a mirrored lv had only about 60% throughput compared to unmirrored.

    greetings
    Joachim


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