Can I convert a raid10 array to raid0?

I have created a raid10 array using mdadm. Metadata version is 1.2. I want to convert this to a raid0 array, is it possible?

P.S. I am having terabytes of data, I want to avoid copying the data over.

Yes.

As of mdadm version 3.2.1, and running a "suitably recent kernel" (whatever that means, I'd guess at least 3.0), a reshape from RAID10 to RAID0 is possible. This means a pretty recent Linux distribution; the system that you're running on may need an upgrade, or you may need to temporarily boot to a live CD type of environment with newer tools to do the conversion.

To make the change, it'll be something along these lines:

mdadm /dev/md0 --grow --level=0
resize2fs /dev/md0

And do keep in mind the caveats that have been mentioned. Running anything on RAID0 is incredibly risky; you will see a failure eventually.

No.

What you CAN do is remove the mirrors from the RAID-10 array, make those new spares into a new RAID-0 array, move all data over, and then add the remaining drives to the new RAID-0 array.

If mdadm supported growing RAID-0 arrays. Which it doesn't.

Switch to LVM instead.