I have a Dell Poweredge 1800 with 4 Cheetah 10K.7 Ultra U320 SCSI Drives which are supposed to be mirroring each other in case of failure of one hard drive the exact same thing is on the others. Drives 1 & 4 show failure. When turning it the server won't boot up and shows "No Boot Device Available." If Drives 2 and 3 are truly a mirror of 1 and 4, I am assuming that if I could put Drive 2 in place of Drive 1, the server may boot. When I do this, the screen reads that "SCSI Drives not found at correct positions. Drive roaming done by firmware." Is there anyway to place working Drive 2 in slot 1 and change the utility configuration so a good drive will be in slot one and I can see if it will boot up?

Hi!
This is a quite serious matter to be solved. The information you have provided is not enough at all.
What you have to include in here:

1. First, Be precise. Don't assume.
2. How did you recognized the failure. Which indicators or POST/BIOS/RAID BIOS reported you the errors? Was it from the OpenManageSA?
3. Please specify the Hardware Controller model and manufacturer with the version (RAID controller).
4. Which Operating System do you run (or ran)?
5. Are these disks Hot Swappable?
6. Have you used hardware RAID controller or software RAID? Provided by OS.
7. Do you have Dell OpenManage Server Administrator?
8. How do you describe the RAID configuration? Are you sure that Disk 1 and 4 are mirrored to 2 and 3? You must be precise. Because raids can be used in many ways. You can combine any two disks and mirror them to any two disks. Even though it prevents hard drive failures, if your OS had an issue Mirrors may not be an option to recover it.
9. That message is a Warning Message. However Drive Roaming has completed. You don't need to worry about that.
10. If your BIOS has associated firmware controllers you could rebuild the array. But you may have to add new disks to replace others. You may need to update the firmware if necessary.
11. Then if you plan to use disk 2 and 3, you have to position them to 1 and 4. Then try to rebuild the array. But you may have to have Controller Drive installed on the disk. That varies from type to type. So I cannot say exactly. However if the mirroring of the OS is done to one disk, that disk would be enough. But you have to be certain. Reconfiguring should be done using both the disks replaced if you do not know anything about the configuration.
12. Check BOOT ORDER. Change it if necessary. If disks fail again check one by one and repair them using a separate machine.
13. Use Dell Software (OpenManage Server Administrator, if its the one available). Rebuild and or Resync the array.
14. If boot record errors occur, you have to boot from CD/DVD and repair the Boot Record and/or MBR.
15. If you need any other issue like BSOD, please write them down. Make sure the OS is not corrupted. If you backed up the System Status, restore it in such a case. Do an In-place Upgrade otherwise (will replace the OS files only, not data).
16. Use the manuals for Dell Server and RAID Controller if you do not know how to use properly.
17. If all the options are not working, you have to contact an engineer at Dell.