NFSv4
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NFSv4, network file system version 4, is the new version of NFS (for setting up the older NFSv3, see Nfs) with new features like strong authentication and integrity via Kerberos and SPKM-3, improved performance, safe file caching, lock migration, UTF-8, ACLs and better support for Windows file sharing semantics.
This article covers installing and configuring NFSv4.
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Installing
Both client and servers require the nfs-utils package. Install with pacman:
# pacman -S nfs-utils.
Configuring
Server
The server configuration is very thorough.
Exports
First we'll need to edit our exports in /etc/exports. A typical NFSv4 export would look like this:
/export 192.168.0.12(rw,fsid=0,no_subtree_check,async,no_root_squash) /export/music 192.168.0.12(rw,no_subtree_check,async,no_root_squash)
/export is the NFS root here (due to the fsid=0 entry). Everything else that you want to be shared over NFS must be accessible under /export.
For exporting directories outside the NFS root, see below.
Exporting directories outside your NFS root
To do this, you'll need to use bind mounts. For example, to bind /home/john to /export/john:
# mount --bind /home/john /export/john
Then, /export/john needs to be added to /etc/exports:
/export 192.168.0.12(rw,fsid=0,no_subtree_check,async,no_root_squash) /export/music 192.168.0.12(rw,no_subtree_check,async,no_root_squash) /export/john 192.168.12(rw,no_subtree_check,async,no_root_squash,nohide)
The nohide option is required, because the kernel NFS server automatically hides mounted directories. To add the bind mount to /etc/fstab:
/home/john /export/john none bind 0 0
ID mapping
Then, /etc/idmapd.conf needs to be edited. You'll need to at the very least specify your Domain there. Example:
[General] Verbosity = 1 Pipefs-Directory = /var/lib/nfs/rpc_pipefs Domain = archlinux.org [Mapping] Nobody-User = nobody Nobody-Group = nobody
File-systems
Add the following lines to /etc/fstab:
rpc_pipefs /var/lib/nfs/rpc_pipefs rpc_pipefs defaults 0 0 nfsd /proc/fs/nfsd nfsd rw,nodev,noexec,nosuid 0 0
Starting the server
To start the NFS server, just do:
# /etc/rc.d/rpcbind start # /etc/rc.d/nfs-common start # /etc/rc.d/nfs-server start
If you want to tweak the configuration, feel free to edit /etc/conf.d/nfs-server.conf to fit your needs.
Client
The client configuration is more simple.
Client ID mapping
/etc/idmapd.conf needs to be edited on all clients and the Domain entry should be identical to the one on the server. Example:
[General] Verbosity = 1 Pipefs-Directory = /var/lib/nfs/rpc_pipefs Domain = archlinux.org [Mapping] Nobody-User = nobody Nobody-Group = nobody [Translation] Method = nsswitch
Client file-systems
Add the following line to /etc/fstab:
rpc_pipefs /var/lib/nfs/rpc_pipefs rpc_pipefs defaults 0 0
Mounting the partitions on the client
On the client, to mount the NFSv4 partition: Make sure that nfs module is loaded. (lsmod | grep nfs). If not execute the next command "modprobe nfs"
# /etc/rc.d/rpcbind start # /etc/rc.d/nfs-common start # mount -t nfs4 server:/ /mnt/server/ # mount -t nfs4 server:/music /mnt/music/ # mount -t nfs4 server:/john /mnt/john
Replacing 'server' with the hostname or IP address of your NFS server and of course 'server', 'music' and 'john' with the names of whatever directories you exported on the server.
If you want the NFS volumes to mount automatically on bootup, add them to fstab.
Client & Server: Time Synchronization
In order for NFS to function properly, both server and client must have closely matching time values. If the clocks on the clients differ from the server too much, then basic functions like file copy operations may hang for a very long time leaving the system unusable until they resume. The clocks do not have to match to micro/nano second accuracies, but ideally they should be within 1 second of each other.
The NTP system is recommended to sync both the server and the clients to the highly accurate NTP servers available on the Internet. For a small system like a home network, the ntpdate utility may be used to sync both servers and clients to the same time. For a larger installation, it may be desirable to install an OpenNTP server (see NTP) onto the same machine acting as the NFS server, and then all clients on the network would sync time values from the server. This has the advantage of lowering the stress on the external NTP servers, and in assuring that the NFS clients will use the exact time that the NFS server has, even if the NFS server experiences some drift.
Troubleshooting
Common problems and how to overcome them
messages.log contains "nfsdopenone: Opening /proc/net/rpc/nfs4.nametoid/channel failed: errno 2 (No such file or directory)"
Add 'nfsd' to /etc/rc.conf modules array (NOTE: you may need to add "Verbosity = 3" to /etc/idmapd.conf and restart the services above to receive the error)
exportfs: /etc/exports:2: syntax error: bad option list
Delete all space from the option list in /etc/exports
mount.nfs4: No such device
Check that you have loaded nfs module
lsmod | grep nfs
and if previous returns empty or only nfsd-stuff, do
modprobe nfs