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    SubjectRe: [ANNOUNCE] Ramback: faster than a speeding bullet
    > So now you can ask some hard questions: what if the power goes out 
    > completely or the host crashes or something else goes wrong while
    > critical data is still in the ramdisk? Easy: use reliable components.

    Nice fiction - stuff crashes eventually - not that this isn't useful. For
    a long time simply loading a 2-3GB Ramdisk off hard disk has been a good
    way to build things like compile engines where loss of state is not bad.

    > If UPS power runs out while ramback still holds unflushed dirty data
    > then things get ugly. Hopefully a fsck -f will be able to pull
    > something useful out of the mess. (This is where you might want to be
    > running Ext3.) The name of the game is to install sufficient UPS power
    > to get your dirty ramdisk data onto stable storage this time, every
    > time.

    Ext3 is only going to help you if the ramdisk writeback respects barriers
    and ordering rules ?

    > * Previously saved data must be reloaded into the ramdisk on startup.

    /bin/cp from initrd

    > * Cannot transfer directly between ramdisk and backing store, so must
    > first transfer into memory then relaunch to destination.

    Why not - providing you clear the dirty bit before the write and you
    check it again after ? And on the disk size as you are going to have to
    suck all the content back in presumably a log structure is not a big
    concern ?

    > * Per chunk locking is not feasible for a terabyte scale ramdisk.

    And we care 8) ?

    > * Handle chunk size other than PAGE_SIZE.

    If you are prepared to go bigger than the fs chunk size so lose the
    ordering guarantees your chunk size really ought to be *big* IMHO


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