From ab700c0368ddffc0736f69d4e56d8800815716f2 Mon Sep 17 00:00:00 2001
From: Alexander Heldt <me@alexanderheldt.se>
Date: Thu, 1 Oct 2026 07:39:53 +0000
Subject: [PATCH] manatee: Cap ZFS ARC at 4 GiB

---
 hosts/manatee/disk-config.nix | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hosts/manatee/disk-config.nix b/hosts/manatee/disk-config.nix
index ac99534..2c88ffc 100644
--- a/hosts/manatee/disk-config.nix
+++ b/hosts/manatee/disk-config.nix
@@ -86,6 +86,9 @@
 
     services.zfs.autoScrub.enable = true;
 
+    # Cap the ARC at 4 GiB (default is ~all of RAM); leaves room for services on this low-memory host.
+    boot.kernelParams = [ "zfs.zfs_arc_max=${toString (4 * 1024 * 1024 * 1024)}" ];
+
     # Don't force-import the pool if it appears in use elsewhere; safer default in 26.11+.
     boot.zfs.forceImportRoot = false;