Chapter 13 Compliance, Storage & Ops Admin: #pSystem

Storage Engines (SQLite, MS SQL Server, PostgreSQL 18), Clustering & Updater

SharpMailserver cleanly separates structured metadata and full-text indexes from SHA-256 deduplicated, Zstandard-compressed MIME blobs (-62% disk footprint). Choose freely among three first-class SQL engines with zero Redis, Elasticsearch, or Kafka dependencies.

Operational Tip & Architecture Note

Before applying any in-place update, the built-in 1-Click Updater (#pSystem) cryptographically verifies the SHA-256 digest against SHA256SUMS.txt while strictly preserving appsettings.Production.json, TLS certificates, and mailbox data.

Sample Storage Configuration in appsettings.Production.json

Choose 'Sqlite' (single node), 'SqlServer' (Windows / Azure SQL), or 'Postgres' (Linux HA cluster).

Reference / Configuration

{
  "Storage": {
    "Provider": "SqlServer",
    "ConnectionString": "Server=sql01.intern;Database=SharpMail;Integrated Security=True;TrustServerCertificate=True;",
    "BlobDirectory": "D:\\SharpMailserverData\\blobs"
  }
}

Settings, Default Values & Best Practices

Setting / Location	Description	Default Value	Production Best Practice
`SQLite WAL (Storage:Provider = Sqlite)`	Zero-config embedded database running in Write-Ahead-Logging (WAL) mode with built-in FTS5 search and zero external daemons.	`Standard für Einzelserver`	Ideal for single-node deployments up to ~250 active mailboxes on local SSD/NVMe storage (never place SQLite WAL files on network SMB/NFS shares!).
`Microsoft SQL Server (SqlServer)`	First-class Microsoft.Data.SqlClient engine for SQL Server 2019-2025, Express, Docker, and Azure SQL with sp_getapplock clustering and zero-addon search.	`READ_COMMITTED_SNAPSHOT auto`	Top choice for Windows Server infrastructure: works out of the box even on SQL Server Express without requiring OS Full-Text Search add-ons.
`PostgreSQL 18 (Postgres)`	High-throughput active-active cluster engine leveraging LISTEN/NOTIFY (< 2 ms push), UNLOGGED tables, and pg_try_advisory_lock.	`Empfohlen für Linux-Cluster`	Reference engine for 500 to 100,000+ mailboxes and multi-node Active-Active Linux/Kubernetes clusters.
`1-Klick-System-Updater (#pSystem)`	Checks /api/releases/latest, verifies SHA-256 checksums, stages binaries, and restarts the Windows Service or systemd unit seamlessly.	`SHA-256-geprüft`	Trigger 1-click updates directly from #pSystem (or via install.sh --update / MSI wizard) with automatic reconnect once the new version boots.