diff --git a/installer/functions b/installer/functions
index 14451973d..c4a00a5b5 100644
--- a/installer/functions
+++ b/installer/functions
@@ -239,3 +239,61 @@ websocketcommand() {
         echo "EError timeout"
     fi
 }
+
+# Check space requirements on CHROOTS partition
+# $1: the partition's minimum size threshold
+# $2: the partition's minimum available space threshold
+check_space() {
+    local part="${CHROOTS:-/usr/local}"
+    df -m "$part" | awk 'FNR == 2 {print $2,$4}' | {
+        read -r size avail
+        if [ "$size" -lt "$1" ]; then
+            local size_gb="$((${size}/1000))GB"
+            echo -n "WARNING: Your CHROOTS partition is rather small" 1>&2
+            echo " (${size_gb})." 1>&2
+            echo "WARNING: Usually $((${1}/1000))GB or more is recommended." 1>&2
+            return 1
+        elif [ "$avail" -lt "$2" ]; then
+            local avail_gb="$((${avail}/1000))GB"
+            echo -n "WARNING: Your available space for CHROOTS is rather" 1>&2
+            echo " small (${avail_gb})." 1>&2
+            echo "WARNING: Usually $((${2}/1000))GB or more is recommended." 1>&2
+            return 2
+        else
+            return 0
+        fi
+    }
+}
+
+# Check if partition 7 / ROOT-C (dual-boot installs) has been resized
+# normally called when space requirements on the CHROOTS partiton aren't met
+check_dualboot() {
+    local disk="$(rootdev -s -d)"
+    local dualboot_part="$(rootdev -s | sed 's/.$/7/')"
+    local dualboot_size="$(cgpt show -i7 -s "${disk}")"
+    if [ "$dualboot_size" -gt 1 ]; then
+        echo "WARNING: Partiton 7, normally used for dual-boot installs, has been resized" 1>&2
+        local tmp="`mktemp -d --tmpdir=/tmp 'check-dualboot.XXX'`"
+        local unmount="umount -l '$tmp' 2>/dev/null && rmdir '$tmp'"
+        addtrap "$unmount"
+        if ! mount -o ro "$dualboot_part" "$tmp" 2>/dev/null; then
+            mount "$dualboot_part" "$tmp" 2>/dev/null
+        fi
+        df -m "$tmp" | awk 'FNR == 2 {print $2,$4}' | {
+            read -r size avail
+            local dualboot_size_gb="$((${size}/1000))GB"
+            local dualboot_avail_gb="$((${avail}/1000))GB"
+            echo "WARNING: to ${dualboot_size_gb} with ${dualboot_avail_gb} free." 1>&2
+        }
+        distrib="$(awk -F= '/DISTRIB_DESCRIPTION=/ {print $2}' < \
+            "$tmp/etc/lsb-release" 2>/dev/null)"
+        if [ -n "$distrib" ]; then
+            echo "WARNING: (It appears to have $distrib installed.)" 1>&2
+        fi
+        undotrap
+        eval "$unmount"
+        return 1
+    else
+        return 0
+    fi
+}
diff --git a/installer/main.sh b/installer/main.sh
index 86ef1afbc..ddbdc46b8 100755
--- a/installer/main.sh
+++ b/installer/main.sh
@@ -14,6 +14,8 @@ INSTALLERDIR="$SCRIPTDIR/installer"
 HOSTBINDIR="$SCRIPTDIR/host-bin"
 TARGETSDIR="$SCRIPTDIR/targets"
 SRCDIR="$SCRIPTDIR/src"
+AVAILMIN=2000 # in MB
+SIZEMIN=4000  # in MB
 
 ARCH=''
 BOOTSTRAP_RELEASE=''
@@ -366,6 +368,14 @@ addtrap "stty echo 2>/dev/null"
 BIN="$PREFIX/bin"
 CHROOTS="$PREFIX/chroots"
 
+# Check if space requirements have been met.
+# If not, check for dualboot.
+if ! check_space "$SIZEMIN" "$AVAILMIN"; then
+    check_dualboot || true
+    echo "Press Ctrl-C to abort; installation will continue in 5 seconds." 1>&2
+    sleep 5
+fi
+    
 if [ -z "$RESTOREBIN" ]; then
     # Fix NAME if it was not specified.
     CHROOT="$CHROOTS/${NAME:="${RELEASE:-"$DEFAULTRELEASE"}"}"