To that day, I think no RAID controller supports TRIM on RAID, and you cannot TRIM each drive individually because TRIM needs visibility on the file system which "does not exist" if both drive are separated. The only options to TRIM RAID drives involve loosing the data on them.
So currently it looks like 1 SSD will have to do if I want to stick with trim and maintain my drive performance.
It would be "safer", but I've heard people claiming they used their SSD RAID for close to a year without seeing any significant performance issues. If you are the kind of person to reformat his rig every 6-12 months, then chances are you would never notice a difference anyway.
Question: I know that the more you format a SSD the less time it will last. What kind of effect on lifespan would you see if you format 4 times a year on an Intel X-25 M. (also assume regular usage erases)
Well now you got me thinking. I do end up reinstalling my os and formatting every 6-12 months, due to various issues. Maybe this could still be for me yet!
Bingo, it might require a few more steps than just reformatting (like using a manufacturer's "factory restore" utility of some kind), but performance would be preserved. Just make sure there is a "TRIM" utility available that you can use outside of the OS so you can use it from boot (USB, CD, ...).
Most formatting utilities (not including quick format) do a zero-fill on the drive. SSDs actually need to be "one-filled" in order to be erased by software. By zero-filling an SSD, you basically cause massive slowdown until the controller erases all of the blocks that are now filled with zeroes. The best thing to do is use Secure Erase (or Sanitary_erase for OCZ drives if you want) as this essentially resets the volume bitmap maintained by the controller, telling it that all blocks are invalid and can be pre-erased. The advantage is that only the blocks containing zeroes will need to be erased, instead of every block. Check the SSD sticky in this forum for the first Anandtech article, it has a page on Secure Erase.