diff --git a/xCAT-server/share/xcat/install/scripts/pre.rhels8 b/xCAT-server/share/xcat/install/scripts/pre.rhels8
index 66abd34db..11a9ee9d7 100644
--- a/xCAT-server/share/xcat/install/scripts/pre.rhels8
+++ b/xCAT-server/share/xcat/install/scripts/pre.rhels8
@@ -206,6 +206,26 @@ base64decode()
     done
 }
 
+getdisksize()
+{
+	local disk="$1"
+
+	local blah
+	local blocks
+	local name
+
+	while read -r blah blah blocks name
+	do
+		if [ "${name}" = "${disk}" ]
+		then
+			echo "${blocks}"
+			break
+		fi
+	done </proc/partitions
+
+	return
+}
+
 # time to ascertain fstype and PReP/UEFI/legacy
 # also, find first available block device (sda or vda likely)
 # TODO: pick a likely non-SAN target if possible
@@ -242,6 +262,8 @@ then
     echo "part /boot/efi --fstype=$EFIFSTYPE --ondisk=$instdisk --size=256" >>/tmp/partitionfile
 fi
 
+DISKSIZE="$(getdisksize "${instdisk}")"
+
 # TODO: Ondisk detection, /dev/disk/by-id/edd-int13_dev80 for legacy maybe, and no idea about efi. At least maybe blacklist SAN if mptsas/mpt2sas/megaraid_sas seen...
 echo "part /boot --fstype=$BOOTFSTYPE --asprimary --ondisk=$instdisk --size=512" >>/tmp/partitionfile
 echo "part pv.000997 --grow --asprimary --ondisk=$instdisk --size=18432" >>/tmp/partitionfile