Originally, this post was titled: “If you are planning on putting a couple of SSD drives in a RAID 1 (Mirror), don’t.” but after many more hours of calls to Intel and pages of reading I can safely say: “If you are planning on putting a couple of SSD drives in a RAID 1,5,6,10…, go right ahead!”
THE PROBLEM WITH ‘TRIM’:
SSD’s perform two writes for every one you ask them to do. The first write, wipes the data from the memory cell and the second write pops the data into the cell.
SSD’s optionally can use an Operating System command called TRIM which will perform the first write/cell wipe in advance when it determins that memory cells with blocks of data in them, are no longer in use.
Most RAIDs use old the old SCSI protocols which do not support TRIM and so there are (today… but you just know this will get fixed in the future) no way to make TRIM commands work on these controllers.
Intel says there is about a (maximum) 10% performance boost with TRIM and conversly there is a maximum 10% hit without TRIM. However, SSD drives are soooo much faster than conventional disk based drives, the SSD will still, by far, be the best choice for speed and reliablity.
NEW DRIVERS STILL DON’T ALLOW TRIM IN RAID:
New drivers allow you to connect your SSD to RAID controller, but NOT use it in a RAID array.
You may see sites like THIS one that say Intel now has TRIM friendly RAID drivers (version 9.6 or newer) available HERE , but that is not quite accurate. What this means is that you can CONNECT your SSD to those Intel RAID contollers (which are supported by that driver) BUT YOU STILL CAN NOT USE THE SSD IN A RAID; not even a RAID 1 mirror.
Previously if you connected an SSD to a RAID controller (not in a RAID configration… just connected as a single drive on the RAID controller) you would NOT have TRIM, but now you can have TRIM work on a single disk (non-RAID) on an Intel RST (Rapid Storage Technology) desktop RAID adpator.
So to be clear. As of early 2011 the facts are:
- TRIM will work on SATA controllers
- now TRIM will work on SOME Intel RAID contollers when a NON-RAID’ed SSD is attached
- there are NO configrations which support TRIM on RAID’ed SSD drives
- TRIM is NOT required to work on SSD’s
- SSD’s can safely be RAID’ed to any level 0,1,2,5,6,10 …