Switching to lmdb from Berkeley DB

Virtualmin
1
SYSTEM INFORMATION
OS type and version Almalinux 9.7
Webmin version 2.641
Virtualmin version 8.1.0 Pro
Webserver version Apache 2.4.62
Related packages Postfix3-lmdb, Postfix 3.11.2

I want to switch to lmdb in postfix as Berkeley DB is being deprecated.

I know Virtualmin can handle lmdb by default on alma 10 and derivatives but I was wondering if it can do it on my alma 9.7 install.

Ai suggest the following:

Bildschirmfoto 2026-05-14 um 16.04.29
Bildschirmfoto 2026-05-14 um 16.04.291423×1540 228 KB

2

Why not upgrade to Almalinux 10? Just don’t restore anything related to email and check any forwarding that might be on your system.

3

Alma 10 also has outdated postfix, 3.8. I use 3.11.2 from an external repo for TLS Reporting.

I can update these things like php, mariadb for quite a while without upgrading the OS.

I would only do a new install for new OS.

9.7 also now has Quantum cryptography in its policy to enable, I think 9.7 is still good.

4

Virtualmin/Webmin doesn’t care. It uses the tools provided by Postfix for interacting with the databases (e.g. postmap). Virtualmin does not interact directly with the db files in any circumstance.

5

They have docs on it

6

I migrated using a script like this, worked great:

#!/bin/bash
# =============================================
# Generic & Robust Postfix hash → lmdb Migration
# Handles any number of hash: maps automatically
# =============================================

set -e

echo "=== Postfix hash → lmdb Migration (Robust Generic Version) ==="

# 1. Backup
echo "Backing up main.cf..."
cp /etc/postfix/main.cf /etc/postfix/main.cf.hash-backup-$(date +%Y%m%d-%H%M%S)

# 2. Set default type
echo "Setting default_database_type = lmdb"
postconf -e "default_database_type = lmdb"
postconf -e "default_cache_db_type = lmdb"

# 3. Convert ALL hash: to lmdb:
echo "Converting all hash: to lmdb: in main.cf..."
sed -i 's/hash:/lmdb:/g' /etc/postfix/main.cf

# 4. Rebuild maps intelligently
echo "Rebuilding all LMDB maps..."

# Rebuild standard alias map
postalias lmdb:/etc/aliases 2>/dev/null || true

# Find and rebuild all other maps from main.cf
echo "Detecting and rebuilding maps from main.cf..."

# Get all map paths that use lmdb: now
MAPS=$(postconf -n | grep -E '^[a-z_]+_maps' | grep -o 'lmdb:[^, ]\+' | sort -u)

for map in $MAPS; do
    # Remove "lmdb:" prefix
    path="${map#lmdb:}"
    
    if [ -f "$path" ] || [ -f "$path.db" ]; then
        echo "Rebuilding: $map"
        
        # Special case for tls_server_sni_maps (needs -F)
        if [[ "$map" == *sni_map* ]] || [[ "$path" == *sni_map* ]]; then
            echo "  → Using -F flag for SNI map"
            postmap -F lmdb:"$path"
        else
            postmap lmdb:"$path"
        fi
    else
        echo "  → Skipping (file not found): $path"
    fi
done

# 5. Reload
echo "Reloading Postfix..."
systemctl reload postfix

echo ""
echo "=== Migration completed ==="

# Final info
echo ""
echo "Summary:"
postconf -n | grep -E 'default_database_type|compatibility_level'
echo ""
echo "All active LMDB maps:"
postconf -n | grep -o 'lmdb:[^, ]\+' | sort -u

echo ""
echo "✅ Done! The script automatically detected and rebuilt all maps."
echo "You can run this same script on other servers without modification."