Question : Problem: Changing RAID level on the fly

I've got a server with two 136GB hard drives in a RAID 1 array.  I'm using about 85-90% of the storage capacity of this array, and I need to expand.  My choices are:

1. Scrap the two 136GB drives and get two new 300GB drives, staying in RAID 1.
2. Get two more 136GB drives and combine all four of them into a RAID 10 array.
3. Get one more 136GB drives and combine all three of them into a RAID 5 array.

I'm liking options 2 and 3 because I get more additional storage for my money, and I'm not just throwing perfectly good drives in the trash.  However, is there any way to convert a 2-drive RAID1 array into a 4-drive RAID10 array on the fly (i.e. without having to completely back everything up, wipe the drives, and start from scratch)?  

If the answer is "No, you can't change RAID levels on the fly", then can you please point me in the direction of a best practice for backing up my entire hard drive in preparation for migrating to a new RAID level?

My RAID controller is an LSI MegaRAID U320-1.  It can handle RAID 0, 1, 5, 10, or 50.  My preference would be RAID10.

Answer : Problem: Changing RAID level on the fly

Online RAID level migration and expansion on-the-fly is mentioned in the software manual but it doesn't tell you how to do it. Probably add some disks, select an array and select a new RAID level. It's probably straight forward if you install Power Console.

www.lsi.com/files/docs/techdocs/storage_stand_prod/RAIDpage/mr_configsw_ug.pdf (not a very good manual), it may be easier to use WebBIOS, I think the expansion option is under "Configuration Wizard"

As usual before migrating RAID levels on any RAID controller or SAN it is advisable to back up first since anything could go wrong if there is a bad sector on a disk it may stop the migration.

Quite a few controllers allow online RAID level mifrations but sometimes they won't do it without a cache battery.