Moving data to a new set of HDDs

Hey guys,

I tried looking for a way to do this, but most threads i found are for other issues. I'd like to do this without losing my jails/vms/backups etc.

I currently have this hdd setup:

1x 3TB hdd
1x 1TB hdd

Striped: 4TB
Used ~1.5TB

I bought 2 3TB drives, and the setup i want to achieve now is:

3x 3TB drives

RAID 5 6TB

I assume there is no way to somehow remove the 1TB drive from the stripe, add the other 2 and build a raid 5 keeping data intact. So i need a way to...

Moving data to a new set of HDDs