illumos/OmniOS - Wipe disks in order to re-use them from previous zpool

illumos-wipe-disk.sh

#!/usr/bin/ksh93

# This script only wipe same-sized disks for now
SIZE="10000831348736"
LAST_PART=`echo "($SIZE / 1024 / 1024) - 10" | /usr/bin/bc`

# List of disks to wipe
DRIVES="c0t5000CCA26BD0CAFAd0p0 c0t5000CCA26BD116ACd0p0 c0t5000CCA26BD59F6Dd0p0 c0t5000CCA26BD5AAC5d0p0
c0t5000CCA26BD6960Ed0p0 c0t5000CCA26BD6B9CCd0p0 c0t5000CCA26BD6C6D4d0p0 c0t5000CCA26BD6E59Cd0p0"

verifydrives()
  {
    for DRIVE in $DRIVES
      do
        if [ `/bin/ls -1 /dev/rdsk/$DRIVE` ]
          then
            echo "Drive $DRIVE verified."
          else
            echo "Drive /dev/rdsk/$DRIVE does not exists. Aborting"
            exit
        fi
      done
  }

verifydrives

cleandrives()
  {
        for DRIVE in $DRIVES
    do
        echo "Wiping disk /dev/rdsk/$DRIVE"
        echo ""
        echo "Wipe beginning of disk"
        dd if=/dev/zero of=/dev/rdsk/${DRIVE} bs=1M count=10 #>/dev/null 2>&1
        echo ""
        echo "Wipe last part of disk"
        dd if=/dev/zero of=/dev/rdsk/${DRIVE} bs=1M count=10 seek=$LAST_PART
        echo "$DRIVE done"
        echo ""
    done
  }




echo ""
echo "This will irreversibly destroy partition- and filesystem data on drive(s):"
echo "$DRIVES"
echo ""
echo "USE WITH EXTREME CAUTION!"
echo Do you confirm "yes/no":
read choice
  case "$choice" in
    yes|Yes|y) cleandrives $DRIVES
         echo ""
         echo "Drive(s) cleaned."  ;;
     no) echo ""
         echo "Cleaning cancelled."; break ;;
      *) echo ""
         echo "Cleaning cancelled."; break ;;
  esac

If we need to re-use ZFS disks on same or another OS, experience has shown that it is better to wipe clean first and last part of each disk.

For example, if we bring in disks from FreeBSD, which may or may not end up on a FreeBSD server once again, it is important to erase not only the initial 1M block, but also the last one, since that contains a backup copy of the initial partition.

So, we need to wipe first and last few sectors clean, since they may be labeled in different ways, which could cause issues later on.