I had an MD3200 array failure the other day. And so I've decided to re-install the Redhat Operating System on the R710 Dell server and re-setup multipathing.

Here are some of the things that I've done:

1. Install Redhat 5  using the Dell Resource CD and then yum update to 5.9
2. Install the latest BIOS, HBA, PERC etc firmware to the server
3. Install the latest MDSM (Modular Disk Storage Manager) Software. Follow the Dell MD3200 multi-pathing setup information.
4. Update the MD3200 with the latest RAID Controller and Physical Disk firmware
   1. This stops the many weird "Buffer I/O" and other bootup and shutdown error messages
5. Modified multipath.conf to (See below):
   1. Ignore the internal RAID controller of the server
      1. Multipath was probing it and throwing errors
   2. Move multipath bindings file from /var/lib/multipath/bindings to /etc/multipath/bindings to stop "cannot make directory [/var/lib] : Read-only file sytem" error
      1. re-ran rescan_dm_devs after doing this

Boot error messages from multipath attempting to update /var/lib/multipath/bindings file while /var is read only

Ignore the servers internal RAID controller

blacklist {
        #....
	#jm add blacklist for root sda
	device {
		vendor "DELL"
		product "PERC H700"
	}

}

Note: If you add a device to your blacklist and then move your bindings file as below and then re-run the Dell provided rescan_dm_devs script your bindings file will have different device node names
e.g. /dev/mapper/mpath1 may become /dev/mapp/mpath0.

Move bindings file to /etc/multipath/bindings to stop boot error

mkdir /etc/multipath

edit /etc/multipath.conf and add "bindings_file /etc/multipath/bindings" :

defaults {
	user_friendly_names yes
        # added to move bindings file away from
        # /var which was read-only when multipath was trying to update
        # /var/lib/multipath/bindings during each boot
	bindings_file "/etc/multipath/bindings"
        # Begin Dell MD Modification
	max_fds             8192
        polling_interval      5
        # End Dell MD Modification
}

Re-run rescan_dm_devs

Note: If you have your MD3200 volumes already in /etc/fstab you may have to modify your device names if rescan_dm_devs has changed the /dev/mapper/mpathXpY values.

Bootup Errors Solved by applying the latest MD3200 Firmware to RAID Controllers/NVSRAM

Shutdown Errors Solved by Applying the latest Firmware