Bitdefender
Server backups
Sage 50 Server — Ransomware Resilience & Backup Strategy
This document outlines protective layers and backup strategies for your Sage 50 deployment hosted in a Windows Server 2019 VM on Proxmox VE with ZFS storage.
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✅ Resilience Layer Overview
| Layer | Status |
|---|---|
| ZFS Snapshots | Yes — immutable, instant rollback point-in-time protection |
| Scheduled Backups | Yes — daily ZFS-based backups (possibly stored locally) |
| Offline Backups | Not yet — currently no mention of external/offsite isolation |
| VM Isolation | Yes — Windows Server is isolated in Proxmox VM |
| Access Model | Yes — RDP with CALs, admin via /admin, Proxmox console for fallback |
| Firewalling | Possibly — but not yet discussed; no mention of limiting RDP exposure |
| Restore Time (RTO) | Fast — VM restore or rollback in minutes |
| Recovery Point (RPO) | 1 day — if nightly backups are in place |
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✅ Backup Methods
| Method | How-To |
|---|---|
| External USB SSD (manual) | Plug in once/week, zfs send or Proxmox backup job, then unplug |
| NAS with pull-based rsync | Let NAS pull backups from Proxmox — keeps write access minimal |
| Cloud backup gateway | Use something like BorgBackup + Rclone for encrypted offsite copy |
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✅ Resilience Impact by Feature
| Feature | Resilience Level |
|---|---|
| On-host ZFS snapshots | High |
| Immutable off-host backup | Very High |
| VM isolation via Proxmox | Strong |
| Hardened access (RDP + VPN) | Very Strong |
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🔐 Hardening Recommendations
- Enable Cloudflare Tunnel or VPN for RDP access
- Use
mstsc /adminfor admin, and disable unnecessary RDP users - Set backup destinations to read-only after write
- Replicate or export snapshots to a physically separate location
- Run regular restore drills to validate RTO/RPO
🧪 Testing Schedule
| Task | Frequency |
|---|---|
| Snapshot rollback test | Monthly |
| Full VM restore from backup | Quarterly |
| Air-gapped backup rotation | Weekly (manual) |
| Security and access review | Bi-annually |
Summary
Your Proxmox + ZFS + Windows Server 2019 setup already gives you strong built-in defences. By layering external backups and enforcing hardened access, you achieve full-stack resilience against ransomware.