Question : Problem: PowerEdge 2800 and PERC4e/Di configuration with drive swap.

I have a PowerEdge 2800 with a perc 4e/di RAID controller operating in RAID1 with two 72g drives for the OS and storage.  The system originally had two 36g drives in RAID1 using the same hardware.  Those two 36g drives were safely stored with the appropriate array slot labeled on the outside.  

Now, I am needing to pull some data off these 36g drives but am unsure if (and how) to reconfigure the RAID controller so I don't lose data when booting into the OS using the old 36g drives.  I know how to configure the controller, but I remember an "initialize" function that I had to go through when I began using the 72g drives.  

How can I safely boot into the 36g drives w/o losing data?  

Answer : Problem: PowerEdge 2800 and PERC4e/Di configuration with drive swap.

Let me preface this by saying that I don't have any experience with the Perc 4E itself, however this information should be somewhat universal for SCSI RAID direct attached storage.

The disk configuration (number of drives, RAID configuration, etc.) should be stored in two places.  One copy is kept on the controller NVSRam (the Perc4E) and the other copy is kept on the drives themselves.  When the server goes through its POST routine while booting up the Raid controller checks its configuration against the drives and, assuming they match, it will boot up to the OS.

On most controllers that I have worked with if there is a mismatch between the controller configuration and the disk configuration it will stop the POST and give you a few options.  

One option is to boot normally which attempts to use the configuration on the controller.  This will not work for you because the controller config won't match the config on the drives.

Another option should be to "copy configuration from disks to the controller" or something similar.  This is the option that you need.  It will copy the config from the drives back to the controller boot to the OS.

If your server is in warranty it wouldn't hurt to call Dell's tech support and run this by them.  Go ahead and ask to be escalated at least once or twice so that you get a real tech, not someone reading from a script.

DO NOT, under any circumstances, select an option that allows the controller to initialize the disks.  You will lose all the data on your disks and the only recovery option will be a very expensive data recovery ($thousands!)

As with any procedure involving the disks make sure you get a good backup of your current disks first.  If you don't trust your backup 100% don't think about doing this.

It is quite possible that the "copy configuration from drives to the controller" option is not available during POST.  You may have to boot to your controller configuration utility CD to get this option.  I can't say for sure since I haven't used this particular controller.


Once the procedure is complete you can put your first set of disks back in and copy the configuration from the drives to the controller again.