How to Migrate to a New Synology NAS

My old DS918+ started throwing volume warnings at 2am on a Tuesday, which is exactly the kind of timing these boxes seem to prefer. I had a shiny DS923+ sitting in its box for a month, waiting. That night I finally had a reason to move.

Migrating a Synology sounds terrifying until you understand that Synology built two very different roads for it, and both work. One physically moves your drives. The other copies everything over the network while the old unit keeps running.

Picking the right road is most of the battle. Let me walk you through both, and the traps I have watched people fall into.

First, figure out which migration path fits your situation

There are two supported methods, and they solve different problems. The drive transplant (Synology calls it migration by moving drives) physically pulls your disks out of the old NAS and slots them into the new one. Your data, volume, and most settings ride along on the drives themselves.

The second method is Migration Assistant, a package that clones one running NAS to another over your network. Your old NAS stays intact the whole time, which is a huge safety net.

Here is the quick decision table I use with readers.

Back up first, because migration is not a backup

I know, you want to skip this. Do not skip this.

A drive transplant that goes wrong can leave you staring at a volume that will not mount, and Migration Assistant can stall halfway on a flaky switch. Neither of those is a disaster if you have a current copy somewhere else.

The cheapest insurance is a USB drive attached to the old NAS running Hyper Backup, or a cloud target. If you want to understand why one copy is never enough, the 3-2-1 backup rule from Backblaze explains it in plain terms.

Method one: the drive transplant, step by step

This is the method I reach for when I am keeping the same disks. On good hardware it is genuinely a fifteen minute job.

1. Update DSM on the old NAS first. Get it fully current under Control Panel, Update and Restore. The new NAS wants a DSM version equal to or newer than the drives it is receiving.
2. Shut the old NAS down properly. Use the power menu in DSM, never yank the cord. Wait for the lights to go fully dark.
3. Move the drives in the same order. Bay 1 to bay 1, bay 2 to bay 2. This matters for SHR and RAID sets. That phone photo pays off here.
4. Do not insert your own drives into the new NAS beforehand. If the new unit already has initialized disks, it may want to wipe. Start with it empty.
5. Power on the new NAS and find it. Open find.synology.com or the Synology Assistant desktop app. The unit will report a Migratable status.
6. Follow the migration prompt. Choose to migrate and keep your data and settings. DSM handles the rest and reboots.

The first time I did this, I panicked when the new box asked me to install DSM and I thought it was about to erase everything. It was not. It was offering to migrate, and the wording just scared me. Read the screen carefully and pick the migrate option, not the fresh install.

Method two: Migration Assistant over the network

Use this when you are moving to fresh, larger drives, or when the old NAS has to stay online. Both units need to be on and reachable on the same network.

Install Migration Assistant from Package Center on both the source and the destination. Set up your new drives on the target NAS first, create the storage pool and volume, then run the assistant from the source.

1. Pick the source NAS and let it scan for a compatible destination on the network.
2. Select what to migrate. You can do a full system migration or pick specific shared folders and settings.
3. Kick off the copy and walk away. This is the slow part. A gigabit link moves roughly 100 to 110 MB per second in the real world, so 4TB of data is around 10 to 12 hours. Plan overnight.
4. Do the final switchover. When the copy finishes, the assistant handles a final sync and can transfer the identity so the new NAS takes over cleanly.

A mistake I see constantly: people start Migration Assistant, see the multi-hour estimate, assume it hung, and reboot. Do not. It is working. Go to bed.

Getting your network speed right so the copy does not crawl

Nothing wrecks a migration like a slow link. If your copy is creeping along at 30 MB per second, you are almost certainly bottlenecked somewhere.

Plug both NAS units into the same switch with real cables. Wi-Fi bridges and powerline adapters will murder your throughput. If both boxes have 2.5GbE ports, use them, and confirm the switch supports 2.5GbE too, otherwise you drop back to gigabit.

Link aggregation can help on multi-port models, but for a one-time migration it is rarely worth the fuss. A clean single gigabit line beats a misconfigured aggregated one every time. If you want the background on how these speeds actually translate, Synology's own Migration Assistant knowledge base article covers the requirements in detail.

After the move: the cleanup checklist

You are not quite done when the data lands. Run through this quick list so nothing bites you a week later.

• Check every shared folder mounts and permissions look right for a couple of test users.
• Reinstall and re-license apps that did not carry over, especially Plex and Surveillance Station.
• Update your backup jobs so Hyper Backup points at the new NAS, not the old one.
• Fix any device that connected by IP address rather than hostname.
• Run a storage pool health check and confirm SMART status on the drives.

Keep the old NAS around, powered down, for a week or two before you wipe it. If anything turns out missing, it is your instant fallback. I have never regretted waiting, and I have regretted wiping too soon.

When you are confident it worked

Give it a real week of normal use. Copy files, stream a movie, let the scheduled backups run once. If everything behaves, then and only then do you erase the old drives and repurpose the old box as a backup target.

Related reading: First-Time NAS Setup: A Beginner Walkthrough, How to Set Up NAS Users and Permissions and Btrfs vs Ext4 on Synology: Which File System.

Migration feels high stakes because your whole digital life lives on that thing. Done in the right order, with one solid backup behind you, it is closer to boring than dramatic. Boring is exactly what you want here.