Sun Cluster 3.2 & SCSI Reservation Issues

If you have worked with luns and Sun Cluster 3.2, you may have discovered that if you ever want to remove a lun from a system, it may not be possible because of the scsi3 reservation that Sun Cluster places on the disks.  The example scenario below walks you through how to overcome this issue and proceed as though Sun Cluster is not even installed.

Example:  We had a 100GB lun off of a Hitachi disk array that we were using in a metaset that was controlled by Sun Cluster. We had removed the resource from the Sun Cluster configuration and removed the device with configadm/devfsadm, however when the storage admin attempted to remove the lun id from the Hitachi array zone, the Hitach array indicated the lun was still in use.  From the Solaris server side, it did not appear to be in use, however Sun Cluster has set the scsi3 reservations on the disk.

Clearing the Sun Cluster scsi reservation steps:

1) Determine what DID device the lun is mapped to using /usr/cluster/bin/scdidadm -L
2) Disable failfast on the DID device using /usr/cluster/lib/sc/scsi -c disfailfast -d /dev/did/rdsk/DID
3) Release the DID device using  /usr/cluster/lib/sc/scsi -c release -d /dev/did/rdsk/DID
4) Scrub the reserve keys from the DID device using  /usr/cluster/lib/sc/scsi -c scrub -d /dev/did/rdsk/DID
5) Confirm reserve keys are removed using /usr/cluster/lib/sc/scsi -c inkeys -d /dev/did/rdsk/DID
6) Remove lun from zone on machine or whatever procedure you were trying to complete.

Configuring Persistent Bindings on Solaris 10

If you have tape devices attached to your Solaris 10 host and you often find that after a reboot of the host, the tape devices are no longer in the same order they were before, you can use the following Perl script to configure the /etc/devlink.tab file to make the tape devices persist.  Script is below:

#!/usr/bin/perl

#################################################################

# This script maps fiber attached tape drives to persistently                                       #

# bind to the same device across reboots.                                                                 #

# (C) 2011 Benjamin Schmaus                                                                                 #

#################################################################

use strict;

my($junk,$path,$devices,$dev,$file);

my(@devices,@file);

my $date = `date +%m%d%Y`;

$file = `/usr/bin/cp /etc/devlink.tab /etc/devlink.tab.$date`;

@file = `cat /etc/devlink.tab`;

@file = grep !/type=ddi_byte:tape/, @file;

open (FILE,">/etc/devlink.tab.new");

print FILE @file;

close (FILE);

@devices = `ls -l /dev/rmt/*cbn|awk {'print \$9 \$11'}`;

open (FILE,">>/etc/devlink.tab.new");

foreach $devices (@devices) {

                chomp($devices);

                ($dev,$path) = split(/\.\.\/\.\./,$devices);

                $dev =~ s/cbn//g;

                $dev =~ s/\/dev\/rmt\///g;

                $path =~ s/:cbn//g;

                ($junk,$path) = split(/st\@/,$path);

                print FILE "type=ddi_byte:tape;addr=$path;\trmt/$dev\\M0\n";

}

close (FILE);

$file = `/usr/bin/mv /etc/devlink.tab.new /etc/devlink.tab`;      

exit;