Recover Data From Raid 5

I have dell poweredge 2850 that the RAM slot has broken and I canned get the server to boot, it just beeps no RAM. I have tried swapping RAM and replacing with new RAM but nothing fixes it. I can occasionally get the server to boot for a minute or two before the server blue screens with "Memory Parity Error." The 5 hard disks are in RAID 5 and functional, but the server is not.

PROBLEM:  I need to recover the data from the RAID 5 configuration. How do I do this?

I have access to another functioning 2850 but it has a 6 disk configuration. So, what do I do to get the disks to boot up on the functioning server? Ultimately I just need about 10 gig of data. Ple
byrntbiscuitAsked:
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PowerEdgeTechConnect With a Mentor IT ConsultantCommented:
If you are putting the drives from the dead 2850 into the good 2850, then here is what you will see when you power up for the first time (after putting drives in):

NVRAM mismatch on the controller.  You MUST go to CTRL-M (configuration utility), Configure, View/Add, select Disk View, then save on exit.  You should now be able to boot up to the OS on those disks.

You will do the same thing when putting the original drives back into the good 2850 (or these drives back into the dead 2850 - if you decide to repair it).
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noxchoGlobal Support CoordinatorCommented:
Or if you do not want to play with RAID on 2850 use this tool: http://runtime.org/raid.htm
You can reconstruct RAID with RAID reconstructor and get your data without need to configure RAID physically on another server.
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Thomas_RoesCommented:
I can't fully promise, (I haven't performed this on a Dell 2850, but the raid controller seems very (i mean VERY) similar to the raid controller on certain intel servers I used. The commandline-tool is the same (http://tools.rapidsoft.de/perc/perc-cheat-sheet.pdf), and both appear to be LSI raid controllers.

These controllers store the configuration on both the controller AND on each drive.

Make a very good backup of the good 2850. I don't take any responsibility.

Shutdown both 2850's.

If you take out all drives from the good 2850 BUT mark them well, so you know where they where. (If you need this system later, you have to put them back in the same order!)

Then get all the drives from the failed 2850, and put them in the same slot on the good 2850.

Power on this system. The raidcontroller will detect that the configuration on the drive's is consistent, but different from the controller. The message is a bit cryptic, but you have to accept the foreign configuration. Don't enter the configuration utility, just let the server boot after choosing Foreign configuration.

After getting your data, reverse the procedure to get the other 2850 back online and perform the same "Accept Foreign configuration" action.

This has worked for me on Intel SR2500ALLX systems that very much resemble the Dell 2850. Good luck.

Good luck

Thomas Roes
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PowerEdgeTechIT ConsultantCommented:
Foreign configurations only exist on the newer PERC's ... PERC 5/6/Hxx controllers.  Follow the instructions I gave you for what to do on a 2850 with a PERC 4 when you put in the disks from the other machine!

Do "mark them well" though.  Even though the PERC 4 supports "drive roaming", don't make it harder than it needs to be for the controller to see your data.
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PowerEdgeTechIT ConsultantCommented:
Noxcho ... he would still need a way to access the drives, and without a functioning server to put them into, RR won't do him any good.  If he does put them into a working system, he might as well follow the few keystrokes instruction to import the configuration on the new machine.
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Aaron TomoskySD-WAN SimplifiedCommented:
Any chance the raid controller is a card you can just move to the good server with the drives?
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PowerEdgeTechIT ConsultantCommented:
While it is possible, it is very most likely the onboard PERC 4e/Di ... but a little clarification wouldn't hurt, as this would be a better option if using an add-in PERC 4.  (Although the steps I provided would work regardless of whether they are attached to the onboard or an add-in PERC.)  
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byrntbiscuitAuthor Commented:
I went through that configuration, but I forgot that there were 2 logical drives (C:\ and D:\). So, I changed from one RAID 5 to a RAID 1 (on the 1st two drives) and a RAID 5 (remaining three drives), and IT WORKED! It booted right up! I did not build this server I just used it a few times, so that is why i forgot.
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PowerEdgeTechIT ConsultantCommented:
Good to hear.
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