How do you back up computer files to NAS? I've paired Mac Time Machine and Windows File History before, but without a quota, it almost took up the entire drive

last month, my mom's old Lenovo got stuck spinning when booting, and the first question the computer repair technician asked was, "Do you want anything inside?" At that moment, I remembered that the NAS at home had been running for over half a year, and the phone had automatic photo backup. I had already the phone set, but none of the three computers in the family—my MacBook, my mom's Lenovo, and the desktop in the study—had ever backed up to the NAS. Work documents on the computer, original photos from the past few years—all naked. This article clearly explains the backup routes for Mac and Windows, which I personally installed one by one, and also covers the pitfalls.

first, distinguish: sync is a mirror, backup is a medicine for regret

before you start, there's a concept you must clarify, or else even if you get it, it's pointless. I was lazy at first and directly used Synology Drive to sync the MacBook document directory to the NAS, thinking "having both sides = safe." Later, my hand trembled and I deleted a half-revised spreadsheet, and the NAS file with the same name disappeared too—sync is a mirror, you delete here, delete there, I've written about this pitfall in detail .

backup is different; it keeps the version intact. The Mac Time Machine saves a snapshot every hour by default, and after file changes, it keeps a page. Flipping back can go back to the last Wednesday afternoon version; Windows file history is similar; save copies at your set frequency. Mistaken deletions, corrections, and ransomware are all saved by "going back in time." So my setup is twofold: commonly used documents are synchronized for convenience, and the whole machine is backed up to save life. If the two layers don't conflict, don't use one layer for another.

one more thing to clarify: backing up your computer to the NAS only moves the eggs from one basket to two, and the NAS's own data needs a separate copy. I've written about the 3-2-1 set before, so I won't repeat it here.

Three steps to

NAS the platform: create a folder, start streaming, and set quotas

start with Synology. My main model is the DS220+, DSM 7.2. Step one: In the Control Panel, → shared folders, create a new one, which I call TimeMachine. Don't check advanced items like "Hide for users without permissions." After creating it, just enable read/write permissions for the account you want to back up. the permission set is unfamiliar, refer to my previous post .

Step two, go →to the File Service → Advanced tab in the Control Panel, check "Enable Bonjour Time Machine Broadcast via SMB," click "Set Time Machine Folder" next to it, and select the folder you just created.

Step three is the quota, which is also the pitfall in my article's title. In the same pop-up window, I set the storage limit for devices in this folder. I set the MacBook to 500GB. Why must it be set: The Time Machine has the temper of using up all available space on the target drive before deleting the oldest backups. That's exactly how Apple designed it. If you don't set a quota, it will confidently take up your entire 4TB storage pool. This is how the photo and movie disk alerts come about. I didn't set it up the first time, but half a month later I found that over 700GB of available space had dropped to me, which scared me so much I quickly deleted it, backed it up, and started over.

Feiniu, my N100 small machine is running fnOS. Version 0.8.27 (December 2024) natively supports Time Machine. In the file service SMB settings, you can find the Time Machine-related switch and select a shared folder. Older versions require enabling SSH and manually adding the fruit parameter to the SMB configuration file. You can easily search online tutorials. Beginners, don't mess around—upgrade the system first.

Mac end in two minutes, marking the first full coverage of the

NAS is done, and the Mac side is very fast. System settings → the General → Time Machine → add a backup disk. A drive with the NAS name like "TimeMachine on xxx" will pop up from the list. Select it, enter your NAS account and password, and you're done. After a one-minute countdown, I started running on my own.

Here are two sensory numbers for you to match. I have about 256GB of RAM on my MacBook, and the gigabit intranet ran at full speed for about 40 minutes. The actual SMB speed was around 90MB/s, which is about level my previous internal network transfers. After that, you add data every hour, fix whatever you change, and it's done in seconds—no pop-ups or noise.

the first backup, always plug in the power supply and do not close the lid. The night I first built it, I closed the MacBook and put it in my bag. The next day, when I checked the backup, it stopped at 63% and was completely interrupted. The time machine is tolerant of interruptions and will renew itself, but you always want it to save the first complete one first.

there's a rule set in advance: the Time Machine stores a sparse disk image on the NAS, and all the snapshots of a Mac are packed into this single file. So if two Macs share the same backup folder, it can cause conflicts. Each machine has its own folder and sets its own quota. My wife and I split our MacBooks like this: TimeMachine-A gives 500G, TimeMachine-B gives 300G, and neither interferes.

Windows file history is hidden in the old control panel

my mom's Win11 Lenovo, I use a different setup: File History. This feature isn't available in the Win11 "Settings" app; you need to open the old Control Panel—search for "Control Panel" in the Start menu, then go to "File History."

Before

setup, do one step: → this computer at the top of the "Map Network Drive," enter the path to \192.168.5.10\backup (change the IP to your own; remember to set a fixed IP for the NAS, otherwise if the address changes, the backup will be disconnected), check "Reconnect when logged in," enter your account and password once to save in the credential manager.

Then, in the Control Panel→ file history→ select 'Driver' → 'Add Network Location' on the left side, and select the one you just mapped. Go back to the homepage and click 'Enable' to start running. By default, one page per hour. I changed the retention policy in 'Advanced Settings.' I set it to '10% by storage,' so my laptop wouldn't get full of NAS.

Windows biggest pitfall here: file history is only backed up to the library, desktop, contacts, and favorites by default. My mom saved all the photos in the D drive's "My Photos" section. The first time, I matched it perfectly, but after testing the recovery ability, I realized the D drive wasn't even included in the backup area. The method of supplementation either adds those folders to the "library" or uses junction to attach the directory to the backup location. This step is ninety percent of the tutorial not to mention, but it's the most important.

said to the desktop computer in the study. It contains reinstallable software and rarely operated items. I don't have automatic backups, so I manually copy the storage drive to the NAS on the first day of every month. Automatic backups aren't always better; manually backing up junk data also automatically takes up space.

don't rush to finish after installation—be sure to test and restore the backup yourself, otherwise you'll be unsure whether the backup will work. On the Mac, click the Time Machine icon in the menu bar to enter Time Machine, scroll back layer by layer until you reach the desired version and click Restore. I tried using half of the table I had deleted incorrectly last week and retrieved it exactly from the version from four days ago. Windows is even more straightforward: right-click the file, → properties → previous versions, then select a time point in the list to restore it. My mom now uses this trick to flip through her damaged documents, which is much easier than teaching her to use cloud drives.

the last point of failure, check in this order

I hit several pitfalls in the first week after finishing the setup, all listed here:

First, the NAS is nowhere to be seen in the Mac backup disk list. Ninety percent of the time it's that the Mac and NAS are not on the same network, or the router has AP isolation enabled—devices can't see each other. AP isolation has been discussed in this article about how to check . That time, my Mac connected to guest WiFi, and as soon as I switched back to the mainnet, it was immediately available.

second, Windows File History prompts 'Network location not found.' The credentials are stored, the drive is mapped, and this is still reported. First, ping the NAS—nine times out of ten, the NAS's IP has been changed by DHCP. Binding static IPs to the router for the NAS is a one-time solution.

third, backup times and hard drive hibernation conflict. I set the NAS hard drive to sleep for 20 minutes, with file history refreshing every hour. Each time I had to wake the drive, the start-stop count kept rising , which was unfriendly to the drive. Later, I extended the backup frequency to two hours and reduced the sleep time to 30 minutes, staggering the intervals.

fourth, if you can't connect to the outside and want to back up remotely. The Time Machine and file history only recognize the internal network. If someone at the company wants to back up their MacBook, they must first connect to the home network. Remote access to the NAS to view files is a different matter. QuickConnect those I've written about , but don't expect cloud relays for backups—they're so slow you'd want to smash your keyboard.

the finishing sequence: first create a folder on the NAS and set the quota, then start Time Machine broadcast, then connect it separately on Mac or Windows, watch all the data for the first time, and stagger the retention policy and hibernation time at the end. With the whole family computer configured like this, the NAS storage account is clear—any machine that explodes can be restored to yesterday.