<div dir="ltr">I am having this exact problem with CentOS and have been banging my head against it on and off for months.<div><br></div><div>I was able to mitigate it somewhat by doing something similar to what Moez suggested:</div><div><br></div><div>- In CentOS, a tempfs is a RAM-based emulated disk and is easy to mount up with the right options</div><div>- On boot, my CentOS livecd creates the tempfs and moves all of "/root"'s files over to it</div><div>- Then it sets the home directory for the root user as the tempfs directory, so operations are performed out of it, instead.</div><div><br></div><div>This has helped reduce filesystem thrash on the overlay you mentioned above, and it extends the life of the system but doesn't fix it completely - kind of a bandaid.</div><div><br></div><div>You can track when the livecd is going to explode with "dmsetup status" and watching the far right "number / number" on the live-rw mount. When the smaller number meets the larger number, your filesystem remounts as read only.</div><div><br></div><div>I've been trying to figure out what these numbers represent, and posted <a href="http://superuser.com/questions/900783/dmsetup-status-fields-explained">this Superuser question</a>, but no one seems to know.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 17, 2015 at 10:36 AM, Moez Roy <span dir="ltr"><<a href="mailto:moez.roy@gmail.com" target="_blank">moez.roy@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Thu, Apr 16, 2015 at 4:13 PM, Moez Roy <<a href="mailto:moez.roy@gmail.com">moez.roy@gmail.com</a>> wrote:<br>
> Copying more than 500 MB crashes Fedora Live CD even though there is<br>
> sufficient RAM.<br>
><br>
> It doesn't matter how much RAM your system has, once you copy more<br>
> than 500 MB you will get stuff like "Input/output error" or just plain<br>
> crashes like "Segmentation fault".<br>
><br>
> Why does this happen?<br>
<br>
I think I figured out why this happens.<br>
<br>
The file /usr/lib/dracut/modules.d/90dmsquash-live/dmsquash-live-root.sh<br>
seems to create a 500MB overlay:<br>
<br>
dd if=/dev/null of=/overlay bs=1024 count=1 seek=$((512*1024))<br>
2> /dev/null<br>
if [ -n "$setup" -a -n "$readonly_overlay" ]; then<br>
RO_OVERLAY_LOOPDEV=$( losetup -f )<br>
losetup $RO_OVERLAY_LOOPDEV /overlay<br>
else<br>
losetup $OVERLAY_LOOPDEV /overlay<br>
fi<br>
fi<br>
<br>
Wouldn't it be more efficient if this was tmpfs instead?<br>
<br>
This also affects installing applications in the live environment<br>
where the installed size is more than 500MB.<br>
</blockquote></div><br></div>