I have a 4 disk unRaid array running unRaid version 4.3.3.  All 4 disks are SATA disks.  Initially the BIOS was configured as IDE.  The array runs fine.

 

I have two "can I?", "should I?" questions:

 

1) Can I change the BIOS SATA configuration to AHCI without any risks to the array's operation and/or integrity?

2) Should I do that? What advantages does AHCI buy me?

 

Thanks.

I actually did this a couple of weeks ago.  It did work, but some of my drives lost their assignment when coming back up.  I just reassigned them to their respective positions, started the array and all was well.

 

I wouldn't expect anything from a performance perspective.  I'm not sure that unRAID even uses the functionality that comes with AHCI (hotswap and NCQ).  If it does, I, personally, wouldn't be bothering with hotswap and I just don't know how much unRAID benefits from NCQ yet.  Hopefully someone with more experience can chime in on that.

AHCI should be better but probably will not notice much, if any, performance difference.

 

We have also seen a case using AHCI with certain motherboards (Asus P5B-xx) where certain hard drives (Hitachi 1TB) are not always recognized in the bios from a cold start (power up).  This is undoubtedly a bios problem.