Copying more than 500 MB crashes Fedora Live CD even though there is sufficient RAM

[Moez Roy]

On Thu, Apr 16, 2015 at 4:13 PM, Moez Roy <moez.roy at gmail.com> wrote:
> Copying more than 500 MB crashes Fedora Live CD even though there is
> sufficient RAM.
>
> It doesn't matter how much RAM your system has, once you copy more
> than 500 MB you will get stuff like "Input/output error" or just plain
> crashes like "Segmentation fault".
>
> Why does this happen?

I think I figured out why this happens.

The file /usr/lib/dracut/modules.d/90dmsquash-live/dmsquash-live-root.sh
seems to create a 500MB overlay:

        dd if=/dev/null of=/overlay bs=1024 count=1 seek=$((512*1024))
2> /dev/null
        if [ -n "$setup" -a -n "$readonly_overlay" ]; then
            RO_OVERLAY_LOOPDEV=$( losetup -f )
            losetup $RO_OVERLAY_LOOPDEV /overlay
        else
            losetup $OVERLAY_LOOPDEV /overlay
        fi
    fi

Wouldn't it be more efficient if this was tmpfs instead?

This also affects installing applications in the live environment
where the installed size is more than 500MB.