Synology Alternative: Migrating from DSM to TrueNAS in Practice

Synology alternative is a question that lands on many small and midsize business desks in 2026. Not out of ideology, but because the existing NAS has hit a real ceiling: the price list has moved, the model is being retired, the drives on the vendor HCL no longer match the volume the business needs. TrueNAS is then the obvious candidate. Drawing on several migration projects, we walk through how the switch actually plays out — data copy, pool layout, backup, shares — and where the common tripping points lie.

Why the Synology alternative conversation is louder in 2026

The reasons for looking at the switch are rarely dogmatic. In practice, we see three recurring patterns:

• Price pressure on DSM hardware and expansion units. The upper-tier rack models have moved noticeably, and so have expansion shelves. When a business builds out a larger volume today, the total number is back on the table.
• HDD compatibility lists and a narrower drive selection. DSM insists on drives from a fairly tight list for many of its business boxes. When the drive you need isn’t on it, procurement conversations get tedious quickly.
• Scaling hits the chassis limit. SHR is convenient, but the bay count is finite. Going from 60 to 250 TB means changing either the chassis or the whole system.

Softer factors then pile on — roadmap visibility, the appeal of real data integrity, the prospect of ZFS snapshots without a per-volume limit. All of that makes TrueNAS as a Synology alternative an option worth pricing out. A feature-oriented deep dive lives on our TrueNAS vs Synology comparison — this article is about the migration in practice.

TrueNAS as a Synology alternative — what actually changes

A NAS switch is more than a hardware swap. Two mental shifts matter, so nobody is surprised later.

From finished appliance to storage server

A Synology is a consumer-adjacent appliance concept: unbox it, insert drives, DSM opens a wizard. TrueNAS is a storage operating system running on a real server — either as a DATAZONE appliance (R, H, M, or F series) or as the community edition on your own hardware. That’s an advantage (no vendor lock-in, real server-class components, an open roadmap) and an adjustment: there’s no “one-click photo-sharing app”. TrueNAS is a storage server with an apps catalog focused on what businesses actually need — SMB, NFS, iSCSI, S3, replication, snapshots.

For the sizing conversation, we recommend the TrueNAS configurator: it calculates usable capacity by RAID level, maps the workload onto the right series, and produces a quote that can be reviewed. Price ranges are shown there directly — firm end prices depend on same-day HDD and NVMe pricing and therefore always go through an individual quote at our end.

SHR thinking vs RAID-Z thinking

The biggest conceptual jump is the pool layout. SHR is a convenience layer over mdadm with mixed drives and automatic expansion. RAID-Z (ZFS) thinks differently: a pool consists of one or more vdevs, and the vdev grid decides performance, redundancy, and future expandability.

Practical rules from our projects:

• Same-size drives per vdev. Otherwise ZFS aligns to the smallest one and capacity is lost.
• Number of vdevs drives IOPS, not the number of drives per vdev. Workloads with many parallel requests (virtualization, databases) plan for more, smaller vdevs.
• RAID-Z2 is the default for business storage from eight drives per vdev upward. RAID-Z1 is only for small pools or clearly non-critical data.
• Growth happens by adding whole vdevs, not by inserting individual drives (even though RAID-Z Expansion in current TrueNAS makes stepwise growth possible, the vdev-first mindset stays the safer planning lens).

An 8-bay DSM running SHR-2 typically lands on a 12-bay R-series with two RAID-Z2 vdevs — same redundancy, but headroom for growth without a system swap.

Data migration from Synology to TrueNAS — rsync and SMB in practice

The actual data copy is usually less dramatic than forum threads make it sound. Two paths have proven themselves.

SMB copy — for small volumes and Windows-first admins

Up to roughly 5 TB, and when the migration is going to run over a weekend anyway, SMB is the pragmatic path. Both systems are mounted as shares on the same Windows server or client, then robocopy runs with /MIR /COPY:DAT /R:2 /W:5 /MT:16. Advantages: familiar tooling, decent permissions handling, largely error-free. Downside: slower than a direct link, and with millions of small files the SMB overhead is felt.

rsync over SSH — the path for large or long-running migrations

At double-digit terabytes, or when the migration should run incrementally over several days, rsync wins. On the Synology, rsync is enabled through SSH — as a root-equivalent user, so ACLs come along. On the TrueNAS target, an SSH login with a key is set up and a target dataset is prepared. The classic invocation looks like this (kept as a quote so the syntax stays readable):

rsync -aHAXv —numeric-ids —progress /volume1/source/ user@truenas:/mnt/pool1/target/

The trick is the split between initial and follow-up run: the first sync can run long, then the incremental deltas are small enough to allow a real cut-over at a defined moment. In practice that means one week of preparation, one weekend for the cut-over, no big-bang.

For very large volumes, we also recommend temporarily wiring a direct 10 GbE link between old and new system — that’s the difference between 12 hours and 3 days on 30 TB.

Shares, permissions, ACLs

If Synology today authenticates against Active Directory, finish the TrueNAS AD join before the migration and validate with a test share. Details in our post TrueNAS Active Directory Domain Join. rsync with -aHAXv moves the permissions, but the UID/GID -> SID mapping only makes sense in a cleanly joined domain.

A small note: if the ACLs on the Synology have grown organically (some set locally, some via AD, some by a Mac over SMB), the migration is a good moment to clean them up rather than clone them 1:1. We see this in almost every project — a tidier share is a by-product of the switch.

Snapshots and backup — what replaces Hyper Backup and Snapshot Replication?

The snapshotting story on TrueNAS is a welcome one: snapshots are at the ZFS level, cost almost nothing, and are freely scheduled per dataset. Snapshot Replication becomes ZFS send/receive — usually to a second TrueNAS as a target, either in the same rack or at a second site.

Hyper Backup is typically replaced by a combination:

• ZFS snapshots for the short-term fallback (ransomware, accidentally deleted file).
• Replication to a second TrueNAS for the delayed standby copy — the base of our SMB backup strategy with Proxmox and TrueNAS.
• Cloud Sync into object storage (S3, Backblaze B2, Wasabi) for the offsite copy.

For many small and midsize businesses that produces a 3-2-1-1-0 setup that was hard to build on the old Synology — because DSM-side retention rules, app compatibility, and volume limits kept getting in the way.

The switch step by step in a typical SMB environment

We usually run projects along this outline:

1. Inventory. Which shares, which volumes, which customer processes are attached, which snapshot history has to survive.
2. Size the target. The configurator picks the right series — R for classic file servers, H for virtualization, F for anything latency-critical. For data centers and HA we use the M-series (models M30 and M40 are current; M50 and M60 are EOL and no longer recommended).
3. Network and AD. VLAN, IPs, SMB signing, AD join, DFS-N namespace adjustment if any.
4. Initial sync. Over SMB or rsync, with a clear runtime estimate.
5. Open test shares in parallel — a small user group works against the new structure for a few days before the switch.
6. Cut-over. A Friday-evening rsync delta, DNS/DFS change, Monday morning confirmation.
7. Decommission. The Synology stays online read-only for two to four weeks, then is retired or repurposed as a landing spot for a specific backup copy.

That plan is deliberately conservative. In almost every project we’ve kept reserves in it — an AD join or a DFS-N change can easily uncover an old permission ghost that would otherwise ruin the weekend.

What a migration project realistically costs and how long it takes

We do not publish fixed EUR prices, because HDD and NVMe pricing moves tactically — especially in 2026 with the aftershocks of AI-driven demand. Realistic guidance for a typical SMB switch:

• Hardware: A price frame that becomes transparent through the TrueNAS configurator by series and capacity. Firm quotes come from us or our partners — our TrueNAS Germany partnership post sets the frame. Enterprise models and the M-series run through individual quotes.
• Migration project (services — planning, data copy, AD integration, sign-off): depending on volume and complexity a manageable low to mid four-digit budget; larger environments proportionally more.
• End-user downtime: With clean preparation, one weekend, often only a Saturday.

The question we hear most often at the end: “Why didn’t we do this earlier?” Usually because the fear of the migration was bigger than the migration itself. That may sound flippant, but it matches what we see.

FAQ on the Synology alternative and the TrueNAS migration

Is TrueNAS really the right Synology alternative for a small office?

Yes, if the office wants more than plain file sharing for two or three people. For truly tiny scenarios, entry-level Synology models are convenient, and that will stay true. But once snapshots without volume limits, real data integrity, or planned multi-year scaling matter, TrueNAS — also in its Mini form factor — is the sturdier path.

Do we have to migrate all data at once?

No. In practice we migrate in waves. Large, cold archives run ahead as an initial sync, active shares are pulled over incrementally in a weekend. A big-bang switch is rarely necessary and rarely a good idea.

What happens to the existing Synology snapshots?

DSM snapshots are Btrfs-flavored and can’t be handed over 1:1 to ZFS. The usual approach: freeze a defined retention state on the Synology, migrate it as a full copy, and keep it in a dedicated read-only dataset on TrueNAS for as long as it stays compliance-relevant. Active snapshot history then starts fresh on TrueNAS — but at nearly zero cost and without a hard limit.

Do we have to buy a large enterprise appliance, or is a smaller model enough?

The answer depends on the workload. For classic file-server usage after an SHR-2 predecessor, a model from the R-series is usually enough. For virtualization or databases, the H-series comes in; for data centers and HA the M-series. The TrueNAS configurator helps with sizing without having to comb through datasheets.

What does the backup strategy look like after the switch?

TrueNAS lets you draw 3-2-1-1-0 cleanly: ZFS snapshots as the near-time fallback, replication to a second TrueNAS as the standby copy, Cloud Sync into object storage for the offsite copy. Anyone who has already read our SMB backup strategy with Proxmox and TrueNAS will recognize the same building blocks — but with more control than DSM offered.

How much downtime should we plan for?

In most of our projects, the actual cut-over sits somewhere between two and eight hours on a weekend. The initial sync runs in parallel beforehand, the delta on cut-over evening is small. The prerequisite is clean preparation — especially the AD join, the share names, and the DFS-N layout.