From 7de24b887022d8944e4be0e7615e6365c37c9db5 Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@proton.me>
Date: Mon, 30 Mar 2026 15:37:46 -0400
Subject: [PATCH] fix mq-deadline for hdds: 2

---
 modules/hardware.nix | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/modules/hardware.nix b/modules/hardware.nix
index f0ba280..907729c 100644
--- a/modules/hardware.nix
+++ b/modules/hardware.nix
@@ -44,13 +44,20 @@
       Type = "oneshot";
       RemainAfterExit = true;
     };
+    path = with pkgs; [
+      coreutils
+      gawk
+      zfs
+    ];
     script = ''
-      for dev in /sys/block/sd*; do
-        [ -f "$dev/queue/rotational" ] || continue
-        [ "$(cat "$dev/queue/rotational")" = "1" ] || continue
-
-        # skip removable devices (USB sticks report removable=1)
-        [ "$(cat "$dev/removable")" = "0" ] || continue
+      # Only tune disks in the hdds pool — not all rotational disks.
+      # zpool status gives by-id device names; we resolve to /sys/block/<name>.
+      zpool status hdds | awk '/^\t/ && $1 ~ /^(ata-|nvme-|scsi-)/ {print $1}' | while read -r id; do
+        link="/dev/disk/by-id/$id"
+        [ -L "$link" ] || continue
+        name=$(basename "$(readlink -f "$link")")
+        dev="/sys/block/$name"
+        [ -d "$dev" ] || continue
 
         echo mq-deadline > "$dev/queue/scheduler"
         echo 4096 > "$dev/queue/read_ahead_kb"
@@ -63,7 +70,7 @@
 
         echo 4096 > "$dev/queue/max_sectors_kb" 2>/dev/null || true
 
-        echo "Tuned $(basename "$dev"): mq-deadline, 4M readahead, 15s deadlines"
+        echo "Tuned $id -> $name: mq-deadline, 4M readahead, 15s deadlines"
       done
     '';
   };