Offload Email Storage to a Remote NFS Server

Architecture​

• OpenPanel server — runs websites and mail services (Postfix/Dovecot)
• NFS server — stores /var/mail/ data

Before You Start​

Check your email storage path in OpenAdmin > Emails > Settings you can configure where mail is stored. The default since v1.0 is /var/mail/. This setting is locked once email accounts exist, so check the current value and substitute it in the paths below.

Check your package manager: the commands below assume a Debian-based distro. Replace apt with your distro's package manager if needed.

Step 1: Prepare the NFS Server​

Install NFS:

apt update && apt install nfs-kernel-server

Create the mail storage directory:

mkdir -p /var/mail

Add the export — edit /etc/exports:

/var/mail  <OPENPANEL_SERVER_IP>(rw,sync,no_subtree_check,no_root_squash)

Apply:

exportfs -ra
systemctl restart nfs-kernel-server

Step 2: Configure the OpenPanel Server​

Install the NFS client:

apt update && apt install nfs-common

If mail is already running, stop it:

cd /usr/local/openmail && docker --context=default compose down mailserver

Back up existing mail data:

cp -a /var/mail /var/mail_backup

Create the mount point and mount the NFS share:

mkdir -p /var/mail
mount <NFS_SERVER_IP>:/var/mail /var/mail

Make the mount persistent — add to /etc/fstab:

<NFS_SERVER_IP>:/var/mail  /var/mail  nfs  defaults,_netdev  0  0

Apply:

mount -a

Step 3: Restart Mail Services​

cd /usr/local/openmail && docker --context=default compose up -d mailserver

Verify the mount:

df -h | grep mail

Test​

• Create a new email account and confirm it works
• Delete an existing account and confirm cleanup
• Reboot and confirm the NFS mount persists