Did you see at ANY point a message about a mismatch? Boot to CTRL-M, Configure, View/Add ... are you prompted between Disk View and NVRAM?  If so, select Disk View, then save it on exit. There is a way to reconstruct your array, called a retag, however ... you say you "have no idea which drive is the hot-spare" ... you CANNOT do a retag unless you know which drives were which, including the actual order the drives were in (00-07).  Also, you MUST disable Fast Init before attempting a retag (and do NOT Initialize the array) ... this option is in Objects, Adapter and is ON by default. 1. There will only be data loss if you proceed beyond the system utilities and write to the disk(s) with an installation utility, etc.  You should be able to switch to SCSI then write the contents to an external drive using a RAID recovery utility. 2. The retag, but without knowing even which is the hot-spare, this will not work.  You might assume that it is disk 07, but any assumptions would be unsafe. When you say your original 2600 "died" ... are you able to get as far as the CTRL-M screen or to some POST message(s), or is it seemingly completely dead?
 I have a poweredge 2600 server, which died(suspect motherboard or CPU).  On it were 8 hdds, 7 of which were in a raid5, with the 8th as a hot spare. I have a second poweredge 2600 server, which I swapped the drives into.  The RAID controller did not read the correct config off the drives.  It seems to think the config isn't even on the drives(it's perfectly possible I messed something up in the 'move them to the other server' and nuked the raid config after it didn't read the correct config off the drives, accidentally). I have no idea which drive is the hot spare, nor any of the configs, simply that the person who built the machine would have used 'default'. Questions: 1.  Can I switch the RAID controller to SCSI and still preserve the data on the drives(thus imaging all drives to a ninth spare drive, and play with the images to try and manually reconstruct the RAID array)?  I changed that in bios, but was slightly frightened by the all caps warning of 'you will lose data'.  Is that just talking about the RAID config?  Or will it honestly just randomly start writing to the drives, destroying the data? 2.  Is there a better way to try and reconstruct the array, without going through 8! (40 320) different configurations, assuming i was told the truth that they would have used 'default configs'?
RAID config lost 2600