[Linux-PowerEdge] replacing a failed hard drive with PERC HBA mode

Tim Mooney Tim.Mooney at ndsu.edu
Wed Aug 9 17:14:56 CDT 2017

Hi All!

I need to replace a hard drive in a Dell R720 that's running RHEL 6.9.
The problem is that the replacement drive shows up as "Ready" in the
physical disks area of iDRAC, instead of "Online".  It does not
automatically show up as a vdisk in the virtual disks area.

The PERC H710 mini is in HBA mode, not RAID mode, so it's not handling
the mirroring.  That's being done at the OS level with Linux's mdadm.

This hard drive is part of an mdadm RAID1.  The drive failed completely,
so mdadm failed each of the partitions out of the individual MD devices.
I removed the failed MD components and then forced the OS to forget about
/dev/sdb, with

 	# echo 1 > /sys/block/sdb/device/delete

I pulled the failed hard drive from the hot-swap bay, installed the Dell
replacement drive in the carrier, and inserted the replacement hard drive
into the bay.  The drive LED blinked and went green, and iDRAC shows the
physical disk as "Ready", instead of "Online", and the replacement is
missing completely from the vdisk area.

The OS did not auto-detect a hard drive being added to the bus, and even
a rescan via

 	# echo '- - -' > /sys/class/scsi_host/host0/scan

does not trigger it to recognize the replacement drive is there.  I'm
guessing that's because I need to do something at the PERC/iDRAC/Lifecycle
level to get the drive to switch to "Online" and make it a vdisk.

How do I go about doing that?

We do not currently have any Dell OS-level RPMs installed, so no omsa or
srv-admin or whatever.  After being on this list for a couple of years,
my confidence in those tools is extremely limited.

It seems like 'megaclisas' might be able to help, but I have been
completely unable to find a working link to that tool, after the
LSI->Avago->Broadcomm transition.  If anyone has a working link to get
it, I would appreciate seeing it.

Could 'racadm' via ssh perform the necessary magic to get this drive so
that the PERC is presenting it as a disk to the OS?  Is there something
easier than that, that also doesn't require a huge mess of questionable
Dell RPMs be installed?

Any suggestions are much appreciated,

Tim Mooney                                             Tim.Mooney at ndsu.edu
Enterprise Computing & Infrastructure                  701-231-1076 (Voice)
Room 242-J6, Quentin Burdick Building                  701-231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164

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