Promise TX4650 raid card with OpenFiler

The compatible RAID controllers are listed here:
http://www.openfiler.com/products/hardware-compatibility

Frankly, it is just plain dumb to risk your data to something that hasn't been thoroughly tested and approved for the appliance.  In fact, software RAID is perfectly acceptable, well tested, and would outperform the TX4650 on probably any benchmark you could run.

Buy a supported RAID adapter, or go JBOD.  Your data is worth the extra few dollars it would cost to get something that is certified, is it not?

THe LSI 92xx family is an excellent choice.   I do, however, recommend AGAINST OEM-branded LSI kit.  (HP is almost OK, but only if this is a HP server).  Reason is that the BIOS/firmware/drivers for OEM-branded LSI has an unacceptable lag.  If/when LSI fixes a problem it may be 6 months or longer, if at all, the fix makes it's way to Dell, IBM, and other brands.  Furthermore, the OEM-branded LSI cards are only tested in the DELL/IBM, whatever servers which open you up to headaches if there is an interrupt conflict.   Also if you have problem with a LSI-branded controller you can talk to LSI support.

If you have a Dell flavor, and not in a Dell computer that they support, you are out of luck.

You're exactly right. If you are building a server from parts, stick with retail LSI cards and use a server class motherboard. Desktop class boards don't have the longevity and quality of components to run a NAS or SAN box on.
I had a DELL 2950 with Perc 5i controller, which is an LSI card, and an upgrade of a few drives broke the array due to changes in the drive firmware. It took a few months before Dell had the bios update to fix it.

I have had good results from some of the RocketRaid boards, but I don't have nearly as much confidence as I do with LSI boards.

Will take your advise and install LSI raid instead. Didn't realise at time of purchase that Promise TX raid required drivers for the OS.
Thanks