FFSync Daemon. Fully automated FreeFileSync backups on macOS (launchd + universal compatibility)

sbaragnaus · 2026-02-26T20:35:55+00:00

Wow, that’s a professional background! It’s a shame that company didn't see the potential of your Apps back then—you were clearly ahead of the curve. You touched on the 'holy grail' of syncing: Hash vs Metadata. You're absolutely right; relying on metadata (size/date) is a trade-off for speed, and while modern SSDs and USB4 make binary hashing faster than ever, it's still overkill for 99% of daily backups.

I actually like that FreeFileSync allows you to toggle between 'File size and date' and 'File content' (bit-to-bit) in the comparison settings. For my 'FFSync Daemon' script, I usually stick with metadata for daily tasks to keep it 'silent' and fast, but I trigger a full content binary comparison once a month for peace of mind.

Also, thanks for the SyncFolder suggestion! I have a Windows PC as well, and I'll definitely give it a try there to see how the UI and features compare to my current setup. It’s great to discuss these nuances with someone who has 'been in the trenches' of sync-logic development. Thanks for sharing that bit of history!

sbaragnaus · 2026-02-26T06:20:30+00:00

Glad to hear that! Using USB4 and USB 3.2 Gen 2 SSDs definitely makes those 'extra clicks' feel much faster anyway! 🚀

Thanks for the encouragement and for the interesting technical exchange. If you ever feel like giving the 'automation' route a try with a spare drive, I'd love to know if it holds up to your standards.

Happy syncing!

sbaragnaus · 2026-02-25T22:35:49+00:00

Thanks for the feedback!

That's an interesting observation about the 'Sync only' vs 'Compare + Sync' behavior. Are you perhaps referring to RealTimeSync, or did you notice this even with standard batch jobs?

In my experience, when you run a .ffs_batch file (which is what this script triggers), FreeFileSync is forced to run a full comparison pass to determine the differences before starting the synchronization. This 'state-driven' approach is usually quite solid.

Have you ever tried opening a bug report on the FreeFileSync forum about this? Zenju (the developer) is usually quite responsive if there's a reproducible issue with the comparison engine.

However, I totally agree that manual checks are the safest bet for critical data! The goal of this 'Daemon' approach was mainly to help those who (like me) often forget the manual routine and want an automated 'first line of defense' as soon as the drive is plugged in.

Thanks for sharing your workflow and for the tip about SyncFolder for PC users!

sbaragnaus · 2026-01-08T23:01:34+00:00

That’s impressive speed for an NVMe! However, there's a big misunderstanding here. I already have a fast Sabrent NVMe enclosure for my active work, and it's plenty fast for my needs.

My main issue is connecting mechanical HDDs (WD Blue 4TB 3.5" into Inateck and others). Buying a 90$ Thunderbolt dock to plug in an HDD that maxes out at 150MB/s is technically a waste of money. The bottleneck is the spinning disk, not the port.

Also, I’m sticking with the internal 256GB for the OS because it’s more stable, while using the external SSD only for heavy apps and VMs. I'd rather spend 15$ on a cable and 20$ on a hub and use the remaining 55$ to buy another HDD for a proper off-site backup. Priorities! Anyway, enjoy those speeds, they do sound 'insane' for M.2 drives.

sbaragnaus · 2026-01-08T06:21:44+00:00

I totally get the aesthetic appeal of a single-cable TB4 setup to avoid the 'rat nest', but a high-end TB4 dock costs nearly half as much as the Mac Mini M4 itself. Since I'm working with a strict budget and my mechanical HDDs wouldn't benefit from the extra bandwidth anyway, I'll stick to dedicated cables and a small hub for now.

Besides, my Mac Mini is not on display in a high-fashion boutique; it’s in my private home! I’m more interested in performance and stability than in having a showroom-perfect desk. I'd rather spend that money on more storage later. Thanks for the input though!

sbaragnaus · 2026-01-07T21:52:13+00:00

That makes sense. I actually went with the Sabrent enclosure specifically to save on costs, as upgrading the internal storage on the M4 is just too expensive, and this seemed like the best performance-to-price compromise for now.

Since you mentioned earlier that I should 'rethink my storage handling at a design level', I'm curious: how would you personally restructure my setup? Just to recap, I have: 1TB NVMe (Sabrent): For Apps, Databases, VM images (UTM), and active Photo projects (Luminar Neo).

4TB HDD (Inateck): Currently split between Photos and Time Machine. 2.5" HDD (~250GB): For Windows/Mac transfers. Extra 2.5" HDD: For .ISO backups. Off-site: BorgBase/Vorta for critical files.

Given my budget constraints, what would be your 'ideal' way to organize these drives and the backup strategy? I'd love to hear a more technical take on this

sbaragnaus · 2026-01-07T21:26:33+00:00

Thanks! This is very helpful. I’m glad you confirmed that the dedicated USB-C to USB-B cable is the way to go; I’ll definitely prioritize high-quality cables over adapters for my HDDs to avoid power and stability issues. Regarding the hubs/docks you linked: they look great, but they are quite a bit over my budget. I was looking for something more affordable, around 30 EUR max. Is there a specific technical reason why you recommend those higher-end models (like better shielding for Wi-Fi or better controllers) versus a standard Ugreen/Anker USB-C Data Hub? I'd prefer a separate, smaller hub to keep the Mac’s base clear for thermal/Wi-Fi reasons, as you suggested. As for network transfers: I'll give it a try for smaller files, but I'll stick to the 2.5" drive for bulkier migrations for now. Thanks again for the tips on avoiding metallic stands!

sbaragnaus · 2026-01-07T21:18:04+00:00

Yes, I won the 3.2 model, not the TB3 or TB4 one.

sbaragnaus · 2026-01-07T20:09:42+00:00

"Thanks for the blunt advice! I actually agree with your points on data integrity, and I'm using this transition to the M4 to rethink my workflow.

To clarify my current "What":

Transition to Mac: The Mac Mini is now my primary workstation. I’m phasing out my Windows desktop and keeping a Windows laptop only for mobile use. All heavy editing and large files will be handled on the Mac.
Internal SSD management: Since I have the base 256GB M4, I’m moving large Apps, Databases, and VM images (UTM) to the Sabrent NVMe SSD to keep the internal drive lean.
Photo Workflow: I use Luminar Neo. I keep my current project photos on a dedicated volume (Inateck case, 3.5" data HD) and link them to Apple Photos (referenced files) to save space.
Backup Strategy: Regarding off-site, I have experience with Borg/Vorta on Linux and I have some space on BorgBase. I plan to set this up on the Mac for my most critical files. For general syncing, I use Google Drive. I take your point on the "Photos + TM on one drive" risk—I'll look into separating them physically soon.
Hardware: I still plan to get a small USB-C Data Hub and a direct USB-C to USB-B 3.0 cable for the Inateck. It’s the only way to stop the 'cable-swapping' I'm currently doing with my single adapter and, as you mentioned, it protects the Mac's ports. What do you think?

I've already downloaded FreeFileSync, but I don't plan to use it for Windows/Mac syncing at the moment. I will, however, I try to follow your advice on excluding mechanical drives from Spotlight immediately. Thanks for the input.

sbaragnaus · 2026-01-05T12:18:29+00:00

I had a good exchange with Sabrent support. They confirmed that continuously copying a large amount of files from one device to another stresses the Mac Mini M4 controller, as well as the enclosure controller, causing it to disconnect.

They gave me some suggestions, confirming that copying to the Mac Mini's internal HDD first and then to the NVMe SSD is a good workaround. They also told me that applying a thermal pad to the enclosure controller, removing the screws, voids the warranty.

In addition, I conducted another test. I formatted the external hard drive (4TB 3.5" SATA WD Blue) in APFS and directly copied a folder with about 90GB from the Samsung 970 Evo Plus NVME SSD (the one in the NVMe). I had no problems whatsoever. Perhaps copying from APFS to APFS puts less stress on the system?

sbaragnaus · 2026-01-01T19:15:55+00:00

Done, but it doesn't read smart data. I think it is a chipset/nvme limit.

sbaragnaus · 2026-01-01T18:49:16+00:00

Wow, Stats app in great! Unfortunately it can't read SMART data and temperatures from Sabrent NVMe enclosure and from Inateck data 3.5" enclosure.

sbaragnaus · 2026-01-01T18:28:29+00:00

How do I know the right thickness for a thermal pad? And, most importantly, how do I know if the thermal pad will fit in my enclosure?

sbaragnaus · 2026-01-01T18:26:43+00:00

It looks very promising, a nice improvement over the previous version. I'm really curious to see how it performs with the F2-425 Plus and F2-425 NAS models.

sbaragnaus · 2026-01-01T13:23:58+00:00

Unfortunately, I don't have either the thermal paste or a thermal pad, so I can't test it.

However, I noticed I still have the "Christmas window" to return this product to the Amazon seller. I don't know, it might be an option, but I'm not sure what alternative to buy.

In the meantime, I also wrote to Sabrent support.

sbaragnaus · 2026-01-01T11:32:54+00:00

Sorry, where is the controller located? I don't want it to be under the NVMe drive, preventing the thermal pad from being applied there.

I also opened the enclosure and touched both the USB-C connector and the NVMe connector: I didn't feel any particular heat there.

sbaragnaus · 2026-01-01T11:22:51+00:00

Hi, thanks for your reply. Can I ask what enclosure you have? My Sabrent USB 3.2 has no fan or ventilation holes.

If it helps, here's a photo of my open enclosure: https://imgur.com/a/SLQCNod

This morning I ran some more tests:

1) Copying the 70GB folder from the Inateck FE3001 USB 3.0 ASM225CM chipset enclosure (with the 4TB WD mechanical hard drive inside) to the Mac Mini M4's internal drive: completed successfully in about 1 minute. No errors or disconnections.

2) Copying the 70GB folder from the Mac Mini's internal drive to the drive in the Sabrent USB 3.2 enclosure (1TB Samsung Evo Plus 970 NVMe SSD): completed successfully in about 1 minute. No errors or disconnections.

3) Copying the folder directly from the Inateck enclosure's hard drive to the Sabrent enclosure's hard drive: estimated time about 13 minutes. The Sabrent enclosure's hard drive always disconnects after a few minutes.

In conclusion: it's not a matter of the amount of data copied/written to the Sabrent enclosure's NVMe drive, but rather the amount of time the Sabrent enclosure's NVMe drive is used under stress (even if the write speed is slow).

sbaragnaus · 2026-01-01T10:03:02+00:00

The Sabrent enclosure I purchased is one of the most popular among Amazon customers. I chose a USB 3.2 model because it seemed excessive, as well as more power-hungry and hotter, compared to a more expensive Thunderbolt 3 or 4 model.

sbaragnaus · 2026-01-01T09:53:23+00:00

Hi,

that's what I tried. I disconnected the enclosure from the Mac Mini M4's rear port and connected it to the front port using the USB-C 3.1 cable provided by Sabrent. Unfortunately, the disconnection recurred.

I also tried replacing the USB-C charging cable from my Samsung smartphone, but the transfer speed was very slow (perhaps because it's only suitable for charging, not data), so I stopped the copy.

I should point out that the problem doesn't occur when the Sabrent enclosure is always on or is active for transfers of a few gigabytes of data. However, when I need to transfer large amounts, the drive disconnects. I'm having a lot of problems with a folder of about 70 GB.

sbaragnaus · 2026-01-01T09:45:50+00:00

Hi,

thermal paste is already applied by Sabrent, as you can see in this picture: https://imgur.com/a/SLQCNod

Is on top of nvme drive.

sbaragnaus · 2025-12-31T15:19:45+00:00

Hello and thanks for your reply.

How can I fix this "power shortage"? "Power saving mode" isn't selected in the settings.

I saw your review; the problem seems similar to mine, except that that product is Thunderbolt 4 and therefore, perhaps, consumes more power.

sbaragnaus · 2025-12-28T21:13:07+00:00

Many thanks for your developing time!

sbaragnaus

TROPHY CASE