feat(install): optional SWAP_SIZE carves a swap partition for hibernate

Hibernate needs a resume target outside the pool (swap-on-zvol deadlocks, a long-standing OpenZFS issue), and that's only decidable at partition time. SWAP_SIZE=100G in a config file carves partition 3 (type 8200) physically between EFI and root. Root still takes the remainder and the EFI=1/ROOT=2 numbering contract holds. validate_config rejects malformed sizes and multi-disk layouts. get_swap_partition handles nvme vs sata naming.

This only partitions: formatting, encryption, and the resume chain stay manual for now. The change ran the real velox reinstall on 2026-08-13 (EFI=512M, SWAP=100G, ROOT=remainder).

1 files changed, 17 insertions, 0 deletions

diff --git a/installer/lib/config.sh b/installer/lib/config.sh
index ed54e36..dea65a0 100644
--- a/installer/lib/config.sh
+++ b/installer/lib/config.sh
@@ -17,6 +17,10 @@ LOCALE="en_US.UTF-8"
 KEYMAP="us"
 ENABLE_SSH="yes"        # SSH with root login (default yes for headless)
 NO_ENCRYPT="no"         # Skip filesystem encryption (testing only)
+SWAP_SIZE=""            # Optional swap partition (e.g. "100G") — carved
+                        # between EFI and root so hibernate has a resume
+                        # target outside the pool. Single-disk only; empty
+                        # keeps the original two-partition layout.
 
 # Required fields — installer errors out if any are still empty at install time.
 HOSTNAME=""
@@ -142,6 +146,19 @@ validate_config() {
         ((++errors))
     fi
 
+    # SWAP_SIZE: sgdisk size syntax (digits + K/M/G/T), single disk only —
+    # a per-disk swap on a RAID layout has no defined resume device.
+    if [[ -n "$SWAP_SIZE" ]]; then
+        if [[ ! "$SWAP_SIZE" =~ ^[0-9]+[KMGT]$ ]]; then
+            warn "Invalid SWAP_SIZE '$SWAP_SIZE' (expected e.g. 100G)"
+            ((++errors))
+        fi
+        if [[ ${#SELECTED_DISKS[@]} -gt 1 ]]; then
+            warn "SWAP_SIZE is only supported on single-disk installs"
+            ((++errors))
+        fi
+    fi
+
     if [[ $errors -gt 0 ]]; then
         error "Config validation failed with $errors error(s)"
     fi