### Setup MkDocs Project

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/README.md

Commands to create a virtual environment, activate it, install MkDocs and related packages, and serve the documentation locally.

```bash
python3 -m venv venv
source venv/bin/activate
pip3 install --no-cache-dir mkdocs mkdocs-material pymdown-extensions mike
mike serve
```

--------------------------------

### Mergerfs Setup Script for Systemd

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/quickstart.md

An example script (setup-for-mergerfs) to perform setup tasks before mounting mergerfs, used in conjunction with a systemd service. It uses systemd-notify to signal readiness.

```shell
#!/usr/bin/env sh

# Perform setup
/bin/sleep 10

# Report back to systemd that things are ready
/bin/systemd-notify --ready
```

--------------------------------

### Compare mhddfs and mergerfs Setup

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/project_comparisons.md

Example of setting up mhddfs and mergerfs for similar pooling behavior. Note the different options used for drive pooling and space management.

```bash
mhddfs -o mlimit=4G,allow_other /mnt/drive1,/mnt/drive2 /mnt/pool
```

```bash
mergerfs -o minfreespace=4G,category.create=ff /mnt/drive1:/mnt/drive2 /mnt/pool
```

--------------------------------

### Install Entware for x64

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Install Entware using the generic script for x64 processors.

```bash
wget -O - http://bin.entware.net/x64-k3.2/installer/generic.sh | /bin/sh
```

--------------------------------

### Install Entware for armv5

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Install Entware using the generic script for armv5 processors.

```bash
wget -O - http://bin.entware.net/armv5sf-k3.2/installer/generic.sh | /bin/sh
```

--------------------------------

### Install attr package

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/runtime_interface.md

Install the attr package to get getfattr and setfattr tools on Debian/Ubuntu systems.

```bash
$ sudo apt-get install attr
```

--------------------------------

### Install Entware for armv7

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Install Entware using the generic script for armv7 processors.

```bash
wget -O - http://bin.entware.net/armv7sf-k3.2/installer/generic.sh | /bin/sh
```

--------------------------------

### Build Debian/Ubuntu Package

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/build.md

Install build dependencies, build a Debian package, and install it.

```bash
$ cd mergerfs
$ sudo buildtools/install-build-pkgs
$ make deb
$ sudo dpkg -i ../mergerfs_<version>_<arch>.deb
```

--------------------------------

### mergerfs Runtime Configuration Example

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/runtime_interface.md

Demonstrates retrieving and setting mergerfs runtime configurations, including branches and category create settings.

```bash
[trapexit:/mnt/mergerfs] $ getfattr -d .mergerfs
user.mergerfs.branches="/mnt/a=RW:/mnt/b=RW"
user.mergerfs.minfreespace="4294967295"
user.mergerfs.moveonenospc="false"
...

[trapexit:/mnt/mergerfs] $ getfattr -n user.mergerfs.category.create .mergerfs
user.mergerfs.category.search="mfs"

[trapexit:/mnt/mergerfs] $ setfattr -n user.mergerfs.category.create -v pfrd .mergerfs
[trapexit:/mnt/mergerfs] $ getfattr -n user.mergerfs.category.create .mergerfs
user.mergerfs.category.search="prfd"

[trapexit:/mnt/mergerfs] $ setfattr -n user.mergerfs.branches -v '+</mnt/c=RO' .mergerfs
[trapexit:/mnt/mergerfs] $ getfattr -n user.mergerfs.branches .mergerfs
user.mergerfs.branches="/mnt/c=RO:/mnt/a=RW:/mnt/b=RW"
```

--------------------------------

### Install mergerfs Package

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Install the mergerfs package using the opkg package manager after Entware is set up.

```bash
sudo opkg install mergerfs
```

--------------------------------

### Install mergerfs on NixOS

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Install mergerfs on NixOS using the nix-env command.

```bash
nix-env -iA nixos.mergerfs
```

--------------------------------

### Add SUSE/OpenSUSE repository and install mergerfs

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Add the filesystems repository and refresh zypper, then install mergerfs. Adjust <rel> for your specific OpenSUSE release.

```bash
zypper addrepo https://download.opensuse.org/repositories/filesystems/<rel>/filesystems.repo
zypper refresh
zypper install mergerfs
```

--------------------------------

### Configure mergerfs Mount

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Example mergerfs configuration. Adjust file paths and options according to your specific setup. The 'nonempty' option can be used if the destination directory already contains files like Synology's @eaDir.

```bash
mergerfs -o rw,use_ino,allow_other,func.getattr=newest,category.action=all,category.create=ff,dropcacheonclose=true /volume1/Media/TempMedia:/volume1/Media/GMedia /volume1/Media/FinalMedia
```

--------------------------------

### Systemd Service for Setup Script

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/quickstart.md

A systemd service file (setup-for-mergerfs.service) that runs a setup script before other services. It uses Type=notify to indicate completion.

```systemd
[Unit]
Description=mergerfs setup service

[Service]
Type=notify
RemainAfterExit=yes
ExecStart=/usr/local/bin/setup-for-mergerfs

[Install]
WantedBy=default.target
```

--------------------------------

### Verify mergerfs Installation

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Check if the mergerfs binary is installed correctly by listing the contents of the /opt/bin directory and running the help command.

```bash
sudo ls /volume1/@Entware/opt/bin
```

```bash
mergerfs --help
```

--------------------------------

### Install mergerfs on Debian/Ubuntu

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Download and install the .deb package for Debian or Ubuntu. Replace <ver>, <rel>, and <arch> with the appropriate version, release, and architecture.

```bash
wget https://github.com/trapexit/mergerfs/releases/download/<ver>/mergerfs_<ver>.debian-<rel>_<arch>.deb
sudo dpkg -i mergerfs_<ver>.debian-<rel>_<arch>.deb
```

--------------------------------

### Install mergerfs using static Linux binaries

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Download the static binary tarball and extract it to the root directory. Replace <ver> and <arch> with the appropriate version and architecture.

```bash
wget https://github.com/trapexit/mergerfs/releases/download/<ver>/mergerfs-static-linux_<arch>.tar.gz
sudo tar xvf mergerfs-static-linux_<arch>.tar.gz -C /
```

--------------------------------

### Systemd Service for Mergerfs with Setup Script

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/quickstart.md

A systemd service file for mergerfs that depends on a setup script (setup-for-mergerfs.service) to ensure prerequisites are met before mounting. It includes Requires and After directives.

```systemd
[Unit]
Description=mergerfs /media service
Requires=setup-for-mergerfs.service
After=local-fs.target network.target prepare-for-mergerfs.service

[Service]
Type=simple
KillMode=none
ExecStart=/usr/bin/mergerfs \
  -f \
  -o cache.files=off \
  -o category.create=pfrd \
  -o func.getattr=newest \
  -o dropcacheonclose=false \
  /mnt/hdd0 \
  /mnt/hdd1 \
  /media
ExecStop=/usr/bin/umount /media
# Or if you need fusermount
# ExecStop=/usr/bin/mergerfs-fusermount -u /media
Restart=on-failure

[Install]
WantedBy=default.target
```

--------------------------------

### Install mergerfs on Fedora

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Download and install the RPM package for Fedora. Replace <ver>, <rel>, and <arch> with the appropriate version, release, and architecture.

```bash
wget https://github.com/trapexit/mergerfs/releases/download/<ver>/mergerfs-<ver>.fc<rel>.<arch>.rpm
sudo rpm -i mergerfs-<ver>.fc<rel>.<arch>.rpm
```

--------------------------------

### Install mergerfs using apt

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Install mergerfs using the apt package manager. This is a simple command for Debian-based systems.

```bash
sudo apt install -y mergerfs
```

--------------------------------

### Mergerfs Symlink Setup for Branches

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/quickstart.md

Illustrates how to set up symlinks for mergerfs branches, which mergerfs will resolve to use the real paths. This is useful when using wildcard paths in fstab.

```text
lrwxrwxrwx 1 root root 21 Aug  4  2023 hdd00 -> /mnt/hdd/hdd00
lrwxrwxrwx 1 root root 21 Aug  4  2023 hdd01 -> /mnt/hdd/hdd01
lrwxrwxrwx 1 root root 21 Aug  4  2023 hdd02 -> /mnt/hdd/hdd02
lrwxrwxrwx 1 root root 21 Aug  4  2023 hdd03 -> /mnt/hdd/hdd03
```

--------------------------------

### Install mergerfs on Ubuntu (non-LTS)

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Download and install the .deb package for Ubuntu, potentially using a release most closely related to your non-LTS version. Replace <version>, <ver>, <rel>, and <arch> accordingly.

```bash
wget https://github.com/trapexit/mergerfs/releases/download/<version>/mergerfs_<ver>.ubuntu-<rel>_<arch>.deb
sudo dpkg -i mergerfs_<ver>.ubuntu-<rel>_<arch>.deb
```

--------------------------------

### Build on Generic Linux

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/build.md

Compile and install mergerfs on a generic Linux system with required tools.

```bash
$ cd mergerfs
$ make
$ sudo make install
```

--------------------------------

### Build on FreeBSD

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/build.md

Compile and install mergerfs on FreeBSD with required tools.

```bash
$ cd mergerfs
$ gmake
$ gmake install # as root
```

--------------------------------

### Systemd Service for Mergerfs (Simple)

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/quickstart.md

A basic systemd service file to mount mergerfs on boot. It includes unit, service, and install sections for managing the mergerfs mount.

```systemd
[Unit]
Description=mergerfs /media service
After=local-fs.target network.target

[Service]
Type=simple
KillMode=none
ExecStart=/usr/bin/mergerfs \
  -f \
  -o cache.files=off \
  -o category.create=pfrd \
  -o func.getattr=newest \
  -o dropcacheonclose=false \
  /mnt/hdd0 \
  /mnt/hdd1 \
  /media
ExecStop=/usr/bin/umount /media
# Or if you need fusermount
# ExecStop=/usr/bin/mergerfs-fusermount -u /media
Restart=on-failure

[Install]
WantedBy=default.target
```

--------------------------------

### Mergerfs Autostart Script

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

This script ensures mergerfs is mounted and started automatically on system boot, using the specified configuration options and paths.

```bash
#!/bin/sh

/opt/bin/mergerfs -o rw,use_ino,allow_other,func.getattr=newest,category.action=all,category.create=ff,dropcacheonclose=true /volume1/Media/TempMedia:/volume1/Media/GMedia /volume1/Media/FinalMedia
```

--------------------------------

### Prepare /opt Directory for Entware

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Remove the existing /opt directory and create a new one, then bind mount the Entware directory to /opt.

```bash
rm -rf /opt
mkdir /opt
mount -o bind "/volume1/@Entware/opt" /opt
```

--------------------------------

### Build Options for mergerfs

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/build.md

Demonstrates how to use make to build mergerfs with specific options.

```bash
$ make help
usage: make

make USE_XATTR=0      - build program without xattrs functionality
make STATIC=1         - build static binary
make LTO=1            - build with link time optimization
```

--------------------------------

### Entware Autostart Script

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

This script ensures Entware is mounted and started on boot, and adds its profile to the global profile for system-wide access. It also updates the Entware package list.

```bash
#!/bin/sh

# Mount/Start Entware
mkdir -p /opt
mount -o bind "/volume1/@Entware/opt" /opt
/opt/etc/init.d/rc.unslung start

# Add Entware Profile in Global Profile
if grep  -qF  '/opt/etc/profile' /etc/profile; then
	echo "Confirmed: Entware Profile in Global Profile"
else
	echo "Adding: Entware Profile in Global Profile"
cat >> /etc/profile <<"EOF"

# Load Entware Profile
[ -r "/opt/etc/profile" ] && . /opt/etc/profile
EOF
fi

# Update Entware List
/opt/bin/opkg update
```

--------------------------------

### Build RHEL/CentOS/Rocky/Fedora Package

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/build.md

Install build dependencies, build an RPM package, and install it.

```bash
$ su -
# cd mergerfs
# buildtools/install-build-pkgs
# make rpm
# rpm -i rpmbuild/RPMS/<arch>/mergerfs-<version>.<arch>.rpm
```

--------------------------------

### Collect System Information with mergerfs.collect-info

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/tooling.md

Run this tool to gather system and configuration details for support requests. Ensure mergerfs is mounted before execution and upload the generated file.

```text
$ mergerfs.collect-info
* Please have mergerfs mounted before running this tool.
* Upload the following file to your GitHub ticket or put on https://pastebin.com when requesting support.
* /tmp/mergerfs.info.txt
```

--------------------------------

### Install mergerfs on FreeBSD

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Install mergerfs on FreeBSD using the pkg package manager.

```bash
pkg install filesystems/mergerfs
```

--------------------------------

### Install Entware for armv8 (aarch64)

Source: https://github.com/trapexit/mergerfs/wiki/Installing-MergerFS-on-a-Synology-NAS

Install Entware using the generic script for Realtek RTD129x processors (armv8/aarch64).

```bash
wget -O - http://bin.entware.net/aarch64-k3.10/installer/generic.sh | /bin/sh
```

--------------------------------

### Mergerfs fstab Configuration

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/quickstart.md

Shows how to configure mergerfs using the /etc/fstab file, including an example with options directly in fstab and another using a separate configuration file.

```fstab
/mnt/hdd0:/mnt/hdd1 /media mergerfs cache.files=off,category.create=pfrd,func.getattr=newest,dropcacheonclose=false 0 0
```

```fstab
/etc/mergerfs/branches/media/* /media mergerfs config=/etc/mergerfs/config/media.ini
```

--------------------------------

### Install mergerfs on CentOS/Rocky Linux

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/setup/installation.md

Download and install the RPM package for CentOS or Rocky Linux. Replace <ver>, <rel>, and <arch> with the appropriate version, release, and architecture.

```bash
wget https://github.com/trapexit/mergerfs/releases/download/<ver>/mergerfs-<ver>.el<rel>.<arch>.rpm
sudo rpm -i mergerfs-<ver>.el<rel>.<arch>.rpm
```

--------------------------------

### Enable IO Passthrough with preload.so

Source: https://github.com/trapexit/mergerfs/blob/master/mkdocs/docs/tooling.md

This experimental library overrides file creation and opening to simulate passthrough IO, potentially offering near-native performance. It works with dynamically linked software and may not function with statically compiled applications.

```sh
LD_PRELOAD=/usr/lib/mergerfs/preload.so touch /mnt/mergerfs/filename
```