NGBackup replicates virtual machines and databases with change-block delta transport, continuous log shipping and standby orchestration — then turns a disaster into a one-command failover. Planned, unplanned and sandbox test failover; failback and re-protect; near-zero RPO on continuous modes and seconds-to-minutes RTO. All under a single Director, one queue and one catalog.
Replication is a first-class job type in the Director (not a bolt-on script). The Director schedules cycles, the source plugin computes a delta and the DR receiver applies it — secured end-to-end and recorded in the catalog so every restore point and failover event is auditable.
Dedicated Replicate and Failover job types run in their own scheduler lane with a separate concurrency budget, so DR cycles never starve backups (or vice-versa). State lives in catalog tables: replication pairs, restore points and failover events.
VM plugins push only changed blocks via native change tracking (CBT/RCT/QEMU dirty bitmaps) in a compact binary frame. Database plugins ship logs (WAL, binlog, archived redo, oplog). Seed once, then incrementals forever.
Transport is mutual-TLS or a pre-shared key (ChaCha20-Poly1305 / AES-256-GCM). Bandwidth throttling, exponential-backoff retry, restore-point rotation and sample-block integrity checks are built in.
Veeam-style image replication for five hypervisor platforms. Agentless — driven entirely through the hypervisor API. A first full seed establishes the replica; every cycle after that ships only changed blocks. The replica is provisioned and ready, so failover is a power-on, not a restore.
NGBackup's own engine. The source plugin quiesces the VM (VSS / guest-tools / QEMU guest agent for application consistency), asks the hypervisor "which blocks changed since last cycle?", and streams just those blocks to the DR receiver, which applies them and takes a restore-point snapshot. Interval-driven — typically 5–15 minute RPO.
On Hyper-V, NGBackup can instead drive the hypervisor's own built-in replication (Hyper-V Replica) — enabling it, seeding it and reporting health — while Hyper-V handles transport. Useful where you want Microsoft's native engine with NGBackup as the single control plane. Native RPO is configurable down to 30 seconds.
| Platform | Change tracking | Replication modes | RPO (best) | RTO (best) | Failover set | Instant recovery | Maturity |
|---|---|---|---|---|---|---|---|
| VMware vSphere | VADP + CBT (agentless) | CBT delta-push + seed | 5–15 min | Seconds | Planned · Unplanned · Test · Undo · Permanent · Failback · Re-protect | File-level restore | GA |
| Microsoft Hyper-V | RCT + AVHDX differencing | RCT delta-push + Hyper-V Replica (native async) | 5 min (RCT) · 30 s (native) | Seconds | Planned · Unplanned · Test · Undo · Permanent · Failback · Re-protect | iSCSI live-boot | GA |
| Proxmox VE | QEMU dirty-bitmap (NBD) | Bitmap delta-push + seed | 5–15 min | Seconds | Planned · Unplanned · Test · Undo · Permanent · Failback · Re-protect | Roadmap (SD plugin) | GA |
| Nutanix AHV | Prism CBT (changed-regions) | Bitmap delta-push + seed | Minutes | Seconds | Planned · Unplanned · Test · Undo · Permanent | Roadmap (SD plugin) | RC — code complete |
| Apache CloudStack | QEMU bitmap + xxHash64 dedup | Bitmap delta-push + seed | ~5 min | Seconds | Planned · Unplanned · Test · Failback · Re-protect | Roadmap (SD plugin) | GA |
Graceful switchover: verify source, run a final delta sync, shut the source down cleanly, boot the replica on DR and apply re-IP. Zero data loss.
Source is gone. Pick a restore point, apply it, power on the replica, re-IP, and log the exact data-loss window since the last good cycle.
Boot an isolated clone of the replica on a fenced network — validate your DR plan without ever touching production replication.
Tear down the test/failover VM and snapshot, returning the replica to its pre-failover state. Replication resumes.
Merge restore points into the base disk and detach the replication metadata — the replica becomes standalone production.
After the primary recovers, reverse-sync deltas back and re-establish replication in the original direction.
Map source virtual switches to DR switches and rewrite guest IPs/subnets at failover, so a DR VM lands on the right network without manual reconfiguration.
Disk-format conversion (VMDK ↔ VHDX ↔ qcow2 ↔ raw) means a VM captured on one platform can be restored onto another — Veeam-style V2V, built in.
For databases, replication means continuous log capture and standby orchestration — not snapshots. NGBackup ships engine-native logs (WAL, binlog, archived redo, oplog) and can bootstrap and promote a standby with a single job. Continuous modes reach near-zero RPO; warm standbys reach minute-class RTO.
A daemon tails the engine's transaction log and streams it continuously to Bacula storage. Recovery point shrinks to the log-flush interval — seconds, not minutes.
Replay a full + log chain onto a second host to build a hot/warm standby — then keep it current. Promotion is a single command when disaster strikes.
Demote the old primary, promote the standby, rewire replication — orchestrated by the plugin, validated before it returns success.
| Engine | Replication / standby modes | Continuous capture | RPO (best) | RTO (best) | Maturity |
|---|---|---|---|---|---|
| PostgreSQL | WAL streaming · standby restore · logical-replication capture · block-level incr (PG17+) | CDP — continuous WAL | Near-zero (seconds) | Minutes–hours | GA |
| Oracle Database | Data Guard (EE) · archivelog-apply standby on SE2 · CDP daemon | CDP — archived redo | Near-real-time (EE) · minutes (SE2) | Minutes (standby mounted) | GA |
| Microsoft SQL Server | Log shipping · Always On AG bootstrap · 1→N fan-out | Log backups (≈5 min) | 30 s – 15 min | Minutes (standby in NORECOVERY) | GA |
| MySQL / MariaDB / Percona | Async & GTID replication · Galera/Group · DR-target provisioning | CDP — binlog streamer | ~45–80 s (60 s interval) | Minutes–hours | GA |
| MongoDB | Change-streams tail · oplog tailing · sharded-cluster · switchover (stepDown) | Continuous oplog / streams | Seconds–minutes (30 s resume) | Minutes–hours | GA |
| Informix Dynamic Server | HDR · RSS · SDS · Enterprise Replication — all bootstrap-orchestrated | Logical-log daemon (≥5 s) | < 5 s (interval=5) · < 1 min default | < 5 min (HDR failover) | GA |
| Firebird | Replication-log replay (FB 4+) | Log replay only | Minutes | Hours | Partial |
| Progress OpenEdge | OE-Replication seed bootstrap · AI-archiver shipping | AI-archiver (<15 min) | < 15 min | Minutes (one-shot bootstrap) | Seed only |
| ADABAS | — backup + PITR only — | Not available | Sec–min (PITR) | Hours | No replication |
| HCL Domino / Notes | — roadmap — | Not available | — | — | Pre-alpha |
The archivelog-apply mode bootstraps a physical standby via RMAN and continuously
applies archived redo — on Standard Edition 2 / 23ai FREE. Manual failover with
ACTIVATE STANDBY DATABASE, no EE Data Guard option required.
Continuous WAL streaming for near-zero RPO, plus PG17 pg_basebackup --incremental /
pg_combinebackup block-level chains — and restore directly as a standby.
The logical-log daemon polls sysmaster:syslogs as fast as every 5 seconds, and the
plugin bootstraps HDR, RSS, SDS and Enterprise Replication topologies from one bconsole command.
Binlog streamer sidecar for single-digit-minute RPO, GTID tracking that survives restarts and topology changes, and a donor auto-desync guard so backing up a Galera node never blocks writes.
Mutual TLS 1.3 or a pre-shared key with ChaCha20-Poly1305 / AES-256-GCM. Optional AES-256-GCM at rest on file replicas.
Token-bucket rate limiting with optional business-hours schedules and per-target limits for WAN-friendly DR.
Keep N recovery points per replica (default 7), auto-purging the oldest. Pick any point at failover time.
Exponential backoff (30→60→120 s) with RPO-violation detection and alerts to Bacula messaging.
Sample-block checksums per cycle (Proxmox: 64 KB / FNV-1a, 0 mismatches in gate runs); BLAKE3 on file replication.
Replication pairs, restore points and failover events are catalog rows — queryable, exportable to JSON, ready for Prometheus.
Replication runs in its own lane with a dedicated concurrency budget — DR cadence and backups never contend.
Bootstrap a DR replica from an existing backup to avoid a full WAN copy, then switch to incremental delta-push.
Beyond VMs and DBs: mirror & versioned-retention file replication with multi-site fan-out and failover hooks.
Bring your Veeam, Commvault, NetBackup or Bacula Enterprise renewal quote. We'll match the replication and DR features and cut the price by at least half.