# Packages

- `nfs-utils` (Arch)
- `nfs-kernel-server` (Ubuntu)

# Server

- Create root just for NFS: `/src/nfs`
- Bind locations: `mount --bind /mnt/src /src/nfs/dest`\
  fstab: `/mnt/src /srv/nfs/dest  none   bind   0   0`

## Arch

### `/etc/exports`

| Option            | Description                                                                                      |
|:------------------|:-------------------------------------------------------------------------------------------------|
| `ro` / `rw`       | Clients read only / read-write access                                                            |
| `sync` /          | Server replies after changes by previous request are written to disk                             |
| `async`           | Server does not have to wait                                                                     |
| `wdelay` /        | Server delays committing write requests when it suspects another write request is imminent.      |
| `no_wdelay`       | Disable the delay. Can only be enabled if `sync` is enabled                                      |
| `no_all_squash` / | Does not change the mapping of remote users                                                      |
| `all_squash`      | Squash all remote users including root                                                           |
| `root_squash` /   | Prevent root users connected remotely from having root access (squashing remote root privileges) |
| `no_root_squash`  | Disable root squashing                                                                           |

| Command         |  Description  |
|:----------------|:--------------|
| `exportfs -v`   |  View exports |
| `exportfs -arv` |  Re-export    |

### `/etc/nfs.conf`

- Restrict share to interface
    ```
    [nfsd]
    host=<server-ip/hostname>
    ```

## Ubuntu
### `/etc/default/nfs-kernel-server`
- Disable NFSv3: `RPCMOUNTDOPTS="--manage-gids --no-nfs-version 3"`

### Restarting
```sh
sudo systemctl restart nfs-config
sudo systemctl restart nfs-kernel-server
```

## Performance

### `rsize`/`wsize`

- Check: `cat /proc/fs/nfsd/max_block_size`

`/etc/tmpfiles.d/nfsd-block-size.conf`:
```
w /proc/fs/nfsd/max_block_size - - - - 32768
```

# Client

- `showmount -e <server>`

## Mount
```sh
<server>:/path   /path   nfs   <option> 0 0
```

### Options

#### Mounting

| Option                     | Description                                                                                    |
|:---------------------------|:-----------------------------------------------------------------------------------------------|
| `auto`/`noauto`            |  Will mount/not mount the share until it is accessed                                           |
| `x-systemd.device-timeout` |  How long before give up mounting (seconds)                                                    |
| `x-systemd.idle-timeout`   |  Unmount after idling (seconds)                                                                |
| `timeo`                    |  Time the NFS client waits for a response before it retries an NFS request. (600 = 60 seconds) |
| `hard`/`soft`              |  Continue trying forever / stop after `retrans`                                                |
| `bg`/`fg`                  |  Continue to try mounting / exit with error (when using `mount` command)                       |

#### Performance

| Option                 | Description                            |
|:-----------------------|:---------------------------------------|
| `noatime`/`nodiratime` |  Dont record access time to files/dirs |
| `sync`                 |  Force flushing when writing data      |

# idmapping

- Both server and client
- Check `cat /sys/module/nfs/parameters/nfs4_disable_idmapping`

## `/etc/modprobe.d/nfsd.conf`
```
options nfs nfs4_disable_idmapping=0
options nfsd nfs4_disable_idmapping=0
```