wiki: add manual update guide for Gemini CLI

01-linux/storage/snapraid-mergerfs-setup.md

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+# SnapRAID & MergerFS Storage Setup
+
+## Problem
+
+Managing a collection of mismatched hard drives as a single pool while maintaining data redundancy (parity) without the overhead or risk of a traditional RAID 5/6 array.
+
+## Solution
+
+A combination of **MergerFS** for pooling and **SnapRAID** for parity. This is ideal for "mostly static" media storage (like MajorRAID) where files aren't changing every second.
+
+### 1. Concepts
+
+- **MergerFS:** A FUSE-based union filesystem. It takes multiple drives/folders and presents them as a single mount point. It does NOT provide redundancy.
+- **SnapRAID:** A backup/parity tool for disk arrays. It creates parity information on a dedicated drive. It is NOT real-time (you must run `snapraid sync`).
+
+### 2. Implementation Strategy
+
+1. **Clean the Pool:** Use `rmlint` to clear duplicates and reclaim space.
+2. **Identify the Parity Drive:** Choose your largest drive (or one equal to the largest data drive) to hold the parity information. In my setup, `/mnt/usb` (sdc) was cleared of 4TB of duplicates to be repurposed for this.
+3. **Configure MergerFS:** Pool the data drives (e.g., `/mnt/disk1`, `/mnt/disk2`) into `/storage`.
+4. **Configure SnapRAID:** Point SnapRAID to the data drives and the parity drive.
+
+### 3. MergerFS Config (/etc/fstab)
+
+```fstab
+# Example MergerFS pool
+/mnt/disk*:/mnt/usb-data /storage fuse.mergerfs defaults,allow_other,cache.files=off,use_ino,category.create=mfs,minfreespace=20G,fsname=mergerfsPool 0 0
+```
+
+### 4. SnapRAID Config (/etc/snapraid.conf)
+
+```conf
+# Parity file location
+parity /mnt/parity/snapraid.parity
+
+# Data drives
+content /var/snapraid/snapraid.content
+content /mnt/disk1/.snapraid.content
+content /mnt/disk2/.snapraid.content
+
+data d1 /mnt/disk1/
+data d2 /mnt/disk2/
+
+# Exclusions
+exclude /lost+found/
+exclude /tmp/
+exclude .DS_Store
+```
+
+---
+
+## Maintenance
+
+### SnapRAID Sync
+
+Run this daily (via cron) or after adding large amounts of data:
+
+```bash
+snapraid sync
+```
+
+### SnapRAID Scrub
+
+Run this weekly to check for bitrot:
+
+```bash
+snapraid scrub
+```
+
+---
+
+## Tags
+
+#snapraid #mergerfs #linux #storage #homelab #raid