How to Migrate from Synology to TrueNAS Without Losing Data
9 min read
1,719 words
Migrating from Synology to TrueNAS is a one-way door for most users — once you move your drives, you cannot simply plug them back into the Synology and expect everything to work. The key to a safe transition is a verified backup, a carefully planned pool layout, and keeping your old Synology intact until the new system passes every test. This guide walks you through every step, from prepping your data to configuring shares on TrueNAS SCALE, so you can switch without losing a single file. This guide breaks down migrate synology to truenas in practical terms.
Step 1: Full Verified Backup Before Touching Anything
This is the non-negotiable first step. RAID on a Synology protects against drive failure, but it does not protect against accidental deletion, ransomware, or a botched migration. You need a separate backup of everything you care about before you power down the Synology.
Do not skip this step. A single power surge during the drive transfer could corrupt data on both the old and new systems if no backup exists. A full backup is your safety net.
Use Hyper Backup on the Synology to create an export to an external USB drive or another NAS. For large datasets (10 TB+), consider a direct rsync copy to a temporary server. Verify the backup by restoring a handful of random files — checksums matter, not just file counts. This is also a good moment to review the 3-2-1 backup rule and ensure you have at least two copies in different locations.
Step 2: Planning the TrueNAS Pool Layout
Before you physically move any drives, decide your ZFS pool layout. TrueNAS uses ZFS, which has different requirements than Synology’s Btrfs-based SHR. You cannot simply drop Synology-formatted drives into TrueNAS and expect them to work — ZFS needs its own partition table and pool structure.
Choosing the Right RAID Level for TrueNAS
Your choice depends on drive count and fault tolerance needs. Here is a quick comparison:
| RAID Level | Usable Capacity | Fault Tolerance | Best For |
|---|---|---|---|
| RAIDZ1 | (n-1) drives | 1 drive failure | 3-5 drives, budget-friendly |
| RAIDZ2 | (n-2) drives | 2 drive failures | 5+ drives, higher safety |
| Mirrored vdevs | n/2 drives | 1 per mirror pair | Performance + expandability |
If you are moving from a Synology with SHR-1 (equivalent to RAID 5), RAIDZ1 is the closest match but is not recommended for drives larger than 8 TB due to longer rebuild times. For 12 TB+ drives, RAIDZ2 or mirrored vdevs are safer. Plan your pool now — it is much harder to change later without destroying and recreating the pool.
ZFS pools do not expand easily. If you start with a single RAIDZ2 vdev of 4 drives, adding more drives later requires adding another vdev of at least the same size. Mirrored vdevs are more flexible for incremental expansion — you can add a pair of drives at any time.
Step 3: Can You Reuse Synology Drives Directly in TrueNAS?
No, not without reformatting. Synology formats drives with its own partition scheme (typically ext4 or Btrfs with Synology-specific metadata). TrueNAS requires ZFS, which needs a clean disk with no existing partition table. If you plug a Synology drive into a TrueNAS system, the TrueNAS installer will recognize it as a blank disk and offer to wipe it.
There is no “migration assistant” between Synology DSM and TrueNAS SCALE. You must copy data over the network or via an intermediary storage device. The drives themselves cannot be reused without reformatting.
This means you need enough free space on the TrueNAS side to hold your Synology data — either from new drives or from an external backup that you can restore. If you have a spare set of drives for the TrueNAS build, you can copy data over the network. If you are reusing the same physical drives, you must back up the Synology to external media, wipe the drives in the TrueNAS, create the ZFS pool, and then restore from backup.
Step 4: Migrating Shares, Permissions, and Scheduled Tasks
TrueNAS SCALE uses SMB/CIFS for Windows shares, NFS for Linux, and AFP (deprecated) for older macOS clients. You will need to recreate your Synology shared folders manually in TrueNAS. Here is the process:
Create a dataset for each Synology shared folder (e.g., “Media”, “Documents”, “Backups”). Set the dataset type to “Generic” or “SMB” depending on access method.
In TrueNAS, go to Accounts > Users and create users matching those on the Synology. Note that UID/GID numbers may differ — set them manually to match if you have ACL permissions tied to specific IDs.
Under Sharing > SMB, add a share pointing to each dataset. Enable “Guest Access” only if needed. Apply the same permission settings as your Synology — typically “Read/Write” for specific users, “Read Only” for others.
Synology Task Scheduler equivalents in TrueNAS are “Cron Jobs” under System Settings > Advanced > Cron Jobs. Recreate any rsync, snapshot, or scrub schedules here. For automated backups, use the built-in “Cloud Sync” or “Rsync Tasks” under Data Protection.
Permissions are the trickiest part. Synology uses POSIX ACLs by default, while TrueNAS SCALE uses NFSv4 ACLs for datasets. If you have complex permission structures, export a list of permissions from the Synology (via SSH: getfacl -R /volume1/sharedfolder > permissions.txt) and apply them manually on TrueNAS. For most home users, simple user/group permissions are sufficient — no need to overcomplicate.
Step 5: Keeping the Old Synology Intact Until Verified
This is the golden rule: do not power down the Synology until you have confirmed the TrueNAS system is fully operational. Keep the Synology connected to the network so you can copy data directly over SMB or rsync. Once the TrueNAS is built, follow this order:
- Copy a small test folder (a few GB) from Synology to TrueNAS via SMB — verify file integrity with checksums.
- Copy your largest folders (media archives, photo libraries) — this may take hours over gigabit Ethernet. Expect ~100-110 MB/s on a wired 1 GbE network.
- Run a scrub on the TrueNAS pool to confirm no read errors — this can take 6-12 hours for a 10 TB pool.
- Test access from all clients (Windows, macOS, Linux) — try opening files, editing documents, and streaming media.
- Only after all tests pass, power down the Synology and wipe it for reuse or sell it.
If you are migrating a large media library (10 TB+), consider using rsync over SSH for faster transfer speeds and resumable transfers. The command rsync -avz --progress /path/to/source/ user@truenas-ip:/mnt/pool/dataset/ works well.
Step 6: Post-Migration Verification and Power Optimization
Once all data is on TrueNAS, run a full pool scrub (zpool scrub poolname in the Shell) to verify checksums. Then check your power draw — TrueNAS on DIY hardware often consumes more power than a Synology because of idle spinning drives and less efficient power supplies. You can optimize by enabling HDD power management in TrueNAS (System Settings > Advanced > Power Management) and setting a spin-down timeout of 20-30 minutes for drives that are not accessed frequently.
For a typical 4-drive TrueNAS build with an Intel N100 or Core i3, expect idle power around 25-40W depending on drives. Compare this to a Synology DS920+ which idles at about 15-20W. If power cost is a concern, read our guide on how to reduce NAS power consumption and calculate your annual bill with the NAS cost calculator.
Which Should You Choose: Synology or TrueNAS?
If you value simplicity, automatic app updates, and a polished GUI, Synology is the better choice — stick with it. If you want full control over your storage, ZFS data integrity, and the ability to run Docker containers on bare metal (via TrueNAS SCALE), the switch is worth the effort. For users with 4+ drives who want to avoid Synology’s lock-in, TrueNAS offers a more flexible future. Start with a backup, plan your pool layout, and keep the old Synology online until the new system passes every test. That is the only safe way to migrate from Synology to TrueNAS without losing data.
RAID is not a backup — it protects against drive failure but not against accidental deletion, ransomware, or migration errors.
Frequently Asked Questions
Can I reuse my Synology drives directly in TrueNAS?
No, not without reformatting. Synology drives use a proprietary partition scheme (usually ext4 or Btrfs with Synology metadata), while TrueNAS requires ZFS. If you plug a Synology-formatted drive into a TrueNAS system, the installer will treat it as a blank disk. You must back up your data first, then wipe the drives in TrueNAS, create a ZFS pool, and restore from backup. There is no direct drive migration path.
Do I need to reformat drives when switching from Synology to TrueNAS?
Yes, absolutely. TrueNAS cannot read Synology’s disk format. You must wipe the drives during the TrueNAS installation process, which destroys all data on them. That is why a full backup is mandatory before you start. After reformatting, you create a ZFS pool and restore your data from the backup. Expect this process to take several hours for multi-terabyte datasets.
How do I migrate my file shares and permissions?
You recreate each Synology shared folder as a dataset in TrueNAS, then configure SMB shares pointing to those datasets. User accounts must be recreated manually in TrueNAS — match UID/GID numbers if you have complex ACLs. For simple home setups, basic read/write permissions are enough. Export a list of Synology permissions via SSH using getfacl if you need to preserve granular ACLs, then apply them manually in TrueNAS. This is the most time-consuming part of the migration.
Should I keep my old Synology running during the switch?
Yes, keep the Synology powered on and connected to the network until the TrueNAS system is fully verified. This allows you to copy data directly over SMB or rsync at gigabit speeds (typically 100-110 MB/s). Do not power down the Synology until you have run a scrub on the TrueNAS pool, tested file access from all clients, and confirmed data integrity. Once verified, you can safely repurpose or sell the Synology.
Last verified: July 10, 2026. Specifications cross-checked against manufacturer documentation where available.
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