How to back up and restore NFS export definitions

NFS export definitions decide which local paths clients can mount, which clients may reach them, and which options apply to that access. Backing up those definitions before a risky edit, rebuild, or migration gives the server a known export state that can be restored and reloaded without reconstructing access rules from memory.

Linux NFS servers read export definitions from /etc/exports and files ending in .exports under /etc/exports.d. The active export table is then rebuilt with exportfs, so a complete backup needs the source files plus a verification command that proves the restored definitions are active.

The backup protects export configuration only. It does not back up the shared data under the exported directories, NFS daemon settings such as /etc/nfs.conf, firewall rules, Kerberos keys, or client mount files. Treat the restore step as a configuration rollback because extracting over live export files can remove entries created after the backup.

Steps to back up and restore NFS export definitions:

Record the active export table before creating the backup.
```
$ sudo exportfs -s
/srv/nfs/projects  192.0.2.0/24(sync,wdelay,hide,no_subtree_check,sec=sys,rw,root_squash,no_all_squash)
```
exportfs -s shows active exports in a format close to /etc/exports syntax, which makes the restored state easier to compare later.
Create a restricted backup directory on the NFS server.
```
$ sudo mkdir -p /root/nfs-export-backups
```
Use a root-owned location while the archive is being prepared because export files can reveal internal hostnames, client networks, and security options.

Archive the main export file and export drop-in directory.

$ sudo tar --create --verbose --file /root/nfs-export-backups/nfs-exports-backup.tar /etc/exports /etc/exports.d
/etc/exports
tar: Removing leading `/' from member names
tar: Removing leading `/' from hard link targets
/etc/exports.d/
/etc/exports.d/projects.exports

The archive stores relative paths such as etc/exports so it can be restored under the filesystem root with --directory /.

List the archive contents before changing or moving the server.
```
$ sudo tar --list --file /root/nfs-export-backups/nfs-exports-backup.tar
etc/exports
etc/exports.d/
etc/exports.d/projects.exports
```
The backup should include /etc/exports and every expected drop-in file under /etc/exports.d. Files in /etc/exports.d that do not end in .exports are not read by exportfs.
Copy the archive to the recovery location before editing exports or rebuilding the server.
```
$ sudo cp /root/nfs-export-backups/nfs-exports-backup.tar /var/backups/nfs-exports-backup.tar
```
For rebuild or migration work, keep another copy outside the server being changed. A local-only archive can disappear during a failed rebuild, disk replacement, or rollback attempt.
Restore the saved export definitions when rollback or migration requires the old export table.
```
$ sudo tar --extract --verbose --file /var/backups/nfs-exports-backup.tar --directory /
etc/exports
etc/exports.d/
etc/exports.d/projects.exports
```
This overwrites matching export definition files. If another tool manages a drop-in, confirm that restoring the saved file will not fight the tool's next regeneration pass.
Reload exports from the restored definition files.
```
$ sudo exportfs -rv
exporting 192.0.2.0/24:/srv/nfs/projects
```
exportfs -r synchronizes the active export table with /etc/exports and /etc/exports.d/*.exports, including removals from the saved files.
Confirm the active table matches the restored export options.
```
$ sudo exportfs -s
/srv/nfs/projects  192.0.2.0/24(sync,wdelay,hide,no_subtree_check,sec=sys,rw,root_squash,no_all_squash)
```
Compare the path, client selector, and options with the baseline captured before the change. If the restored table differs, inspect the source file and reload again before sending clients back to the server.
Tool: Config Drift Checker
Test one known client after a migration or emergency restore.
```
$ sudo mount -t nfs4 files.example.net:/srv/nfs/projects /mnt/projects
```
Run this from a client that already has the mount point prepared. A successful client mount proves more than exportfs parsing: DNS or host resolution, firewall access, NFS service state, and exported path permissions must also be correct. Related: How to manually mount an NFS export on Linux