Rebuild Degraded Raid Mirror on DeLL PowerEdge 840 having a SAS5/IR Controller

This article contains step by step instructions for rebuilding a degraded Raid-1 (Raid Mirror) on an LSI / Dell SAS5/IR Controller. More specifically, this article concerns Raid mirrors on the SAS5 IR controller (and the server model is not important). If your server’s Raid mirror is in a degraded state because one of the two disk drives has failed, then you need to replace the failed drive with a compatible new drive and synchronize the Raid Mirror until its status is optimal.  You can determine if the RAID Array is degraded by booting to the Raid Configuration Utility. At server start-up, press CTRL+C to enter the Configuration Utility for the Raid Controller card.  See more specific instructions in “Check Raid Array Status” below.

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Mostly all articles and forum posts addressing this exact subject will recommend that you contact Dell technical support for assistance in understanding the instructions in the Dell SAS5 User Guide. Good luck finding a tech who understands what you are trying to do and who also realizes that the Dell User Guide contains no real help and actually offers misinformation.

BACKUP IMAGE OF DRIVE:  If you have Pre-Install Environment (PE) software CD, like a WIN-PE CD or Bart’s Reatogo version of X-PE CD , then you can and should start the server into some NT-based Operating System from the PE CD and use Symantec Ghost 8 or Acronis true image to create a backup image of the degraded but working primary disk (in case something goes wrong with the sync or rebuild of the Raid Mirror).

CHECK RAID ARRAY STATUS:  To enter the Raid Configuration Utility, power-on the Server and press CTRL-C early during the boot process while the video screen shows that the Raid Card is being initiated. Be ready to press CTRL+C keys simultaneously. If you wait too long to press CTRL+C while the Raid Card is being initiated during POST, then the Operating System may begin to load. In this case, you would need to let the operating system load completely, and then perform a normal shut down / restart in order to try CTRL+C again during POST in order to access the Raid Configuration Utility.

When the Raid Configuration Utility loads, then select the existing Raid Array and press the “Enter” key to begin managing the Array.  Example of Array – “SAS1068”

Select “RAID Properties” to view Disks and Array Properties and status.

If the Array is a Raid-1 (Mirror), then it will show as type “IM” (integrated mirror).  If the Array is Degraded, it might show the following:

Primary Drive – Degraded
Secondary Drive – “Missing”

(Note: Remove the “missing” hard drive and put it into an External SATA / USB drive caddy to test whether the drive is accessible). Connect the USB SATA External Drive caddy to an operating desktop to see if the hard drive is accessible. This article addresses re-synchronizing the Raid mirror when the second drive in the mirror has failed. It does not face what works if the first drive on the mirror fails. In other words, I can only speculate, but my intuitive guess is that you probably do NOT want to flip the physical location of the good drive merely to put it into the first SATA slot, thinking that this might somehow “help” the Array boot better or that the first SATA location would necessarily become the “source” rather than the “target” during the “synch” of the mirror. Note that in most controller configurations, the hard drives normally report themselves as being in positions “0” and “1” and not as “1” and “2.” So, the “00” position would be the first drive on the mirror, and the “01” position would be the second.

REPLACE THE FAILED DRIVE BY INSTALLING A COMPATIBLE NEW DRIVE.  Shut down the operating system and power-off the Dell server.  IMPORTANT:  Make sure that the server’s power cable is connected to an UPS battery back up because synchronization cannot be interrupted by a power failure that will shut down the machine. Replace the Secondary Drive with a Brand New Drive of the same type and size (or larger capacity).  It is recommended to use a drive wth the same size Cache and same Make and Model Hard Drive.  My Primary Drive (Degraded) was Western Digital 500GB SATA II (300Mb/sec) 7200RPM RE2 with a 16MB Cache.  I replaced the Secondary Drive with a brand new (no boot record) Western Digital 500GB SATA II (300Mb/s) 7200RPM RE3 with a 16MB Cache. Both drives are enterprise class.  Buy the Revision 3 (RE3) from www.goharddrive.com. I paid $50 with free ground shipping and my HD arrived in 2 business days in the USA. By the way, I obtained this affiliate link to www.goharddrive.com for referrals because they have good prices, quick delivery and you’ll probably buy there.

G01-0294

REBUILDING / SYNCHRONIZING THE DEGRADED ARRAY.  Start / Power-on the 840 Server and Press CTRL+C to invoke the Raid configuragion utility again. Select the Array name and press “Enter” key. Select “Array Properties,” and noticed that the Secondary Drive will still be reported as MISSING.  Contrary to the SAS5/IR User’s Guide, the existing Raid Array will NOT automatically begin to synchronize or rebuild.   The option to Sychronize Array will be shown in the menu list but it will be grayed-out.  However, the option to Manage Hot Spare will be available.  Contrary to the SAS5/IR User’s Guide, the hot spare is actually supported when a drive drops-off the Array.  In other words, the option to manage hot spare and add hot spare to the array is available when you are adding the second brand new drive to the existing raid mirror array.  The hot spare option is not supported on SAS5/IR for adding a third drive (spare) to an existing Raid Mirror whose status is “Optimal.”

HOW TO INITIATE SYNCHRONIZATION:  In order to commence synchronization from the primary virtual drive (i.e from the degraded array) which will SYNC-over to the brand new secondary physical drive, you must select “Manage Hot Spare.”  On the next menu, you will see for the first time that the Secondary Physical Drive is Actually DETECTED.  The secondary drive should show a few extra MB disk size than the existing primary virtual drive on the degraded mirror.  Use the down-cursor key to move down to the row for the secondary drive, then use the right-cursor key to move over to the HOT SPARE column and press the spacebar in order to change/toggle “NO” to “YES” under the Hot Spare Column for the brand new Secondary physical Drive.  With the secondary showing YES for Hot Spare, then Press C to commit changes to the Array.  Press F3 to confirm committing this change to the Array.  DO NOT CHANGE MENU SCREENS UNTIL AFTER THE “SYNC” IS COMPLETED 100%.

After committing the change to Hot Spare, you will see a menu screen that says:

LSI Corporation Configuration Utility For Dell SAS 5 v6.12.05.00 (2007.09.29)
Manage Array — SAS1068

Identifier:  Dell VIRTUAL DISK 1028
Type:          IM
Scan Order:  0
Size (MB)   476837
Status         0% Syncd

Manage Hot Spare (will be grayed-out)
Synchronize Array (Is available but DO NOT SELECT IT)
Activate Array (will be grayed-out)
Delete Array (Is available but NO NOT SELECT IT)

IMPORTANT:  The Array will take a LONG TIME to achieve a 1% synchronization.  It takes such a long time that it may seem that sync has not begun.  However, SYNC HAS BEGUN!!!  Do NOT exit this current menu screen until SYNC is complete.   Let the synchronization run for as long as it takes to reach 100%.

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