Linux hard drive/device nodes for a Postgres RAID array

[Glen Parker <glenebob@xxxxxxxxxx>]

Hi all, I apologize for asking a Linux question here in the postgres 
list, but I figure somebody here must know the answer, or a better place 
to ask it.

I am building an x86_64 postgres server (see, it isn't JUST about Linux 
:-) with SATA drives and I want to use software RAID for my postgres 
storage.

When Linux boots, it finds all the drives in the system and assigns 
device numbers to them, apparently in the order found.  So, the first 
drive (on SATA port 0 for example) become SDA, the second becomes SDB, 
and so on.  If you have say, four drives, on ports 0,1,2,3, everything 
works fine and you get SDA,SDB,SDC,SDD.

But now, pull the drive from port 2 and boot the system.  You will now 
have SDA,SDB,SDC.  The kernel will now fail BOTH of the last two drives 
from the RAID array.  The one that was SDC is gone, and obviously fails. 
 The one that was SDD is now SDC, so its ID doesn't match what the 
kernel thought it should be, so it fails it too.  If you kill the FIRST 
drive in the array, I believe the entire array becomes inoperable 
because of the resulting shift and ID mismatch.

So the question is, is there some way to "pin" a drive to a device 
mapping?  In other words, is there a way to force the drive on port 0 to 
always be SDA, and the drive on port 2 to always be SDC, even if the 
drive on port 1 fails or is pulled?

-Glen