I have a RAID 10 array with 4 "36" GB HD....that's about 72 GB of available space, but I need more space. How can I add, let's say, another 36 GB HD without having to break the current array, it is, without having to lose the information. Thanx.

You can not do anything to the existing RAID 10 or 0+1 if you like, array as that is the only configuration that works as a RAID 10

However, if you want to add another RAID array to your existing RAID Host Controller, then you should be able to do that.

Do you have a dual-channel RAID controller, say a nice Adaptec board ?!?

If so then add the larger 73~74GB capacity drives to that channel and create a new RAID array. My suggestion is to use a RAID 5 with a hot spare/fix as this will give you striping+mirroring+parity and supports the above mentioned hot spare option

Also note that a RAID 5 array requires a minimum of 3 HD's and of course an extra HD for any hot spares.

Alright, thanx a lot for ur help. Think I'll do that RAID 5 stuff since it's safer than 0+1.

It should work out better for you in the long run as you could copy the data over from your current RAID 10 array to the new RAID 5 array then re-use those drives from the RAID 10 array and wipe out that array and rebuild it as another RAID 5