I had 2 hdds as one spanned volume E: drive on my pc, is there any way of splitting up the drives while still retaining data, one of the drives is giving read errors and want to be able to do damage limitation on data loss.
The simplest solution is naturally backing everything up to another HDD and removing the offending drive. I would be very hesitant to split them without knowing what sort of algorithm is used for distributing the on the disks. If it completely fills one disk and then starts writing to the second, it should be relatively safe. If it uses any sort of load balancing (especially block level), then I wouldn't risk it.
Definitely back up then break it. Most of the time breaking it will make them unreadable individually just like if it was in raid0. Sometimes you may be lucky if you can read some files, but that is only likely if you added a span at a later time when the first disk was nearly full. Generally spanning is a terrible idea. If you need big storage you should be using a more resilient parity scheme in storage spaces, or zfs.
