fix(ansible): optimize root trim policy

Co-authored-by: Junie <junie@jetbrains.com>

ansible/roles/common/tasks/main.yml

@@ -57,6 +57,45 @@
   become: yes
   tags: [swap, optimization]
 
+- name: Check current root mount options
+  command:
+    argv:
+      - findmnt
+      - -no
+      - OPTIONS
+      - /
+  register: root_mount_options
+  changed_when: false
+  tags: [filesystem, optimization, trim]
+
+- name: Ensure root filesystem uses periodic TRIM settings in fstab
+  mount:
+    path: /
+    src: "UUID={{ root_filesystem_uuid }}"
+    fstype: ext4
+    opts: "{{ root_filesystem_mount_opts }}"
+    passno: 1
+    dump: 0
+    state: present
+  become: yes
+  tags: [filesystem, optimization, trim]
+
+- name: Reload systemd after fstab updates
+  systemd:
+    daemon_reload: yes
+  changed_when: false
+  become: yes
+  tags: [filesystem, optimization, trim]
+
+- name: Remount root filesystem without continuous discard
+  mount:
+    path: /
+    opts: "{{ root_filesystem_mount_opts }},nodiscard"
+    state: remounted
+  when: "'discard' in (root_mount_options.stdout.split(','))"
+  become: yes
+  tags: [filesystem, optimization, trim]
+
 - name: Optimize kernel parameters
   sysctl:
     name: "{{ item.name }}"

ansible/vars/main.yml

@@ -1,5 +1,7 @@
 # mw-pfeddersheim-workstation variables
 system_user: mw
+root_filesystem_uuid: 2aeade2e-b169-4964-8cbd-bb7356320b51
+root_filesystem_mount_opts: noatime
 swap_file_path: /swapfile
 swap_file_size_gb: 16
 workspace_root: /home/mw/infrastructure/mw-pfeddersheim-workstation

docs/tech/trim-optimization-2026-04.md

@@ -0,0 +1,75 @@
+---
+description: >-
+  TRIM policy optimization for the mw-pfeddersheim-workstation after the
+  Samsung PM9A1 firmware update to GXA7801Q.
+tags:
+  - storage
+  - trim
+  - nvme
+  - ansible
+  - optimization
+last_updated: '2026-04-02'
+---
+
+# TRIM Optimization After PM9A1 Firmware Update
+
+## Summary
+
+On 2026-04-02 the workstation TRIM policy was aligned with current Linux best
+practice for ext4.
+
+- Root filesystem (`/`) on `/dev/nvme0n1p2` was changed from `noatime,discard`
+  to `noatime` in `/etc/fstab`
+- Weekly `fstrim.timer` remains enabled and active
+- Continuous ext4 discard was disabled at runtime with a remount using
+  `nodiscard`
+
+## Why This Change Was Necessary
+
+The root ext4 filesystem was configured with continuous `discard` while the
+system already had periodic TRIM enabled via `fstrim.timer`.
+
+For ext4, continuous discard adds overhead to unlink and truncate operations.
+With a healthy weekly `fstrim.timer`, it is redundant on this workstation.
+
+## Implementation
+
+The persistent change was implemented in Ansible.
+
+- `ansible/vars/main.yml`
+  - added `root_filesystem_uuid`
+  - added `root_filesystem_mount_opts: noatime`
+- `ansible/roles/common/tasks/main.yml`
+  - ensured the root fstab entry is managed with `mount: state=present`
+  - checked current root mount options with `findmnt`
+  - remounted `/` without continuous discard when needed
+
+## Verification
+
+### fstab
+
+```text
+UUID=2aeade2e-b169-4964-8cbd-bb7356320b51 / ext4 noatime 0 1
+```
+
+### Periodic TRIM
+
+```text
+ActiveState=active
+UnitFileState=enabled
+NextElapseUSecRealtime=Mon 2026-04-06 00:49:28 CEST
+```
+
+### Validation Steps
+
+```text
+ansible-playbook ansible/workstation.yml --check --tags trim
+ansible-playbook ansible/workstation.yml --tags trim
+findmnt --verify --tab-file /etc/fstab
+```
+
+## Notes
+
+- `/boot/efi` remains unchanged
+- This change only targets the ext4 root filesystem TRIM policy
+- Firmware and benchmark documentation remain in the NVMe benchmark documents