Back Up Windows to a NAS (Synology, QNAP, Unraid)

Last updated May 25, 2026

Automated, encrypted Windows backups to a NAS over SFTP, FTPS, WebDAV, or SMB. Works with Synology, QNAP, Unraid, TrueNAS, and any DIY box. On-prem, no monthly fee, full control.

A NAS is the cheapest reliable backup destination you can own outright. One up-front purchase, no monthly bills, and the data physically lives in your closet rather than someone else’s datacenter. BackupKit treats a NAS like any other destination: pick the share, pick a schedule, set encryption and retention, and the job runs unattended. Synology DSM, QNAP QTS, Unraid, TrueNAS, and any DIY box that speaks SFTP, FTPS, WebDAV, or SMB are all supported.

Why NAS for backups

  • One-time cost. A 2-bay Synology or QNAP with two 8 TB drives gives you ~8 TB usable in RAID 1 for under $700 all-in, then no recurring fees.
  • Fast restores. Local gigabit/2.5GbE means terabyte-sized restores happen in hours, not days. Cloud restores at typical home-internet speeds can take a week.
  • Privacy. Your data physically lives in your home or office. No provider holds the keys.
  • No vendor lock-in. Plain files on a network share. If you ever stop using BackupKit, the archives sit there exactly as written.
A NAS isn’t “off-site”

If a fire, flood, or theft takes out your house, it takes the NAS with it. A NAS-only backup strategy isn’t a complete answer. Pair it with a second cloud or S3 job for the 3-2-1 rule (three copies, two media, one off-site).

Which protocol to pick

SFTP (recommended)

Encrypted in transit, single port, built into every modern NAS. Synology calls it “SFTP service,” QNAP calls it “SSH/SFTP”. Best default.

FTPS

FTP with TLS. Works if your NAS doesn’t expose SFTP. Slightly more port/firewall hassle than SFTP.

WebDAV

HTTP-based, easy through firewalls and reverse proxies. Good if you already expose your NAS web UI over HTTPS.

SMB / local drive

Mount the NAS as a Windows network drive (\\synology\backups), then point BackupKit at a local-style path. Fastest on LAN; no cross-WAN.

For backups over the local network, SMB or SFTP are roughly equivalent in throughput. For backups over the internet (NAS at the office, PC at home, or vice versa), use SFTP or WebDAV over TLS — SMB over the internet is a security nightmare.

Step-by-step (Synology example)

  1. Enable SFTP on the NAS. Synology: Control Panel → File Services → FTP → SFTP. Note the port (default 22).
  2. Create a backup user. Don’t use your admin account. Give the user write access to one shared folder, e.g. backups.
  3. Add the SFTP account in BackupKit. Hostname (LAN IP or DDNS), port, username, password. Click test — BackupKit lists the shared folders.
  4. Create the backup job. Source = your Documents/Projects/photo library. Destination = the SFTP account, optionally a subfolder.
  5. Configure. AES-256 encryption with a password, daily/weekly schedule, retention (e.g. keep last 30 days), notifications on failure.
  6. Save and activate. Runs unattended.

QNAP, Unraid, and TrueNAS are the same flow — enable SFTP, create a user, point BackupKit at it.

BackupKit storage picker showing NAS alongside FTP, SFTP and WebDAV
Reach the NAS however it's exposed — a dedicated NAS connection, or SFTP/WebDAV if you prefer.

Encryption: useful even on your own NAS

People sometimes assume backups don’t need encryption if they go to a NAS they own. Two reasons to still enable AES-256:

  • Lost or stolen drives. If a NAS drive walks out (theft, swap, disposal), anyone with a Linux laptop reads the platter contents directly. Encrypted archives are gibberish.
  • Multi-user NAS. Other accounts on the same NAS may eventually have read access through admin rights or misconfiguration. Encrypted archives stay private.

The password is yours. BackupKit never stores it on the NAS.

BackupKit encrypts with AES-256 on your PC before the archive is written. Anyone who reaches the NAS share sees the archive file, not the folder tree inside it.
Your own hardware still benefits: a stolen drive gives up nothing.

Pairing with a cloud job (3-2-1)

The standard recommendation: two BackupKit jobs against the same source. One to the NAS daily (fast, complete history). One to cloud weekly (off-site, disaster proof). Different retention policies if you like — e.g. 60 days on the NAS, 12 weekly versions in the cloud. See the S3 guide for the cloud side.

Three copies of the data: the working copy on your PC, a second on the NAS, and a third in cloud or S3 storage that is off site.
The NAS job is copy two. The rule wants a third, somewhere else.

Common questions

Synology Hyper Backup vs BackupKit?

Hyper Backup runs on the NAS and pulls from your PC (or backs up the NAS itself to cloud). BackupKit runs on your PC and pushes to the NAS. If you want backups initiated from Windows and a single tool managing destinations across cloud + NAS + S3, BackupKit is the simpler fit.

What about restoring a full machine?

BackupKit backs up files and folders, not full disk images. For bare-metal restore, pair BackupKit with a separate disk-imaging tool (Macrium, Veeam Endpoint) and let BackupKit handle the document/project/photo data.

How fast is a typical NAS backup?

Over gigabit LAN, expect 80–110 MB/s sustained. A 100 GB initial backup completes in 15–25 minutes. Subsequent runs only re-upload changed/new archives, so they’re fast.

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