sync-thing and removable drives

ok, i had an idea, and i thought it was a good idea, but mabe its not haha.

currently i have the following setup with sync-thing:

DESKTOP ----------> LAPTOP

desktop has a parent folder named Cloud that syncs all files and child directories to a folder on the laptop called cloud drive.

I received a 1TB ssd external drive from a friend. I have hooked it up to desktop.

Is it possible to sync the “cloud” folder from dekstop to the external drive? I do not need the laptop to sync to the external, just the desktop.

If a change happens on the laptop, it will send it to the desktop like it normally does, then the desktop will sync it to the external drive:) thats my goal:)


Because the 1TB external SSD isn’t capable of running Syncthing, the desktop PC will have to run two instances of Syncthing (Syncthing’s sync process requires Syncthing at both storage endpoints).

Or in other words, one Syncthing instance watches the “Cloud” folder and another Syncthing instance (separate configuration ; different network ports, e.g., 8385 for the web GUI plus 22001 for the sync port) watches the “SSD”.

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ohhhhh i forgot about that piece of information…

well, there went that idea.

wait, what if i used my 128GB samsung fit drive on the laptop and had the desktop sync to that?

this way the laptop is the second instance SAMSUNG MUF-256AB/AM FIT Plus 256GB - 400MB/s USB 3.1 Flash Drive, Gunmetal Gray : Electronics

Yup, that would be fine, and easier to maintain than two independent Syncthing instances on a single computer.

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how bad is the constant read/write gonna kill that fit drive?


In general, read activity doesn’t impact the longevity of a USB flash drive (it’s actually beneficial for refreshing the electrical charge in the NAND gates).

It’s the number of write cycles per block that ultimately wears down flash memory. Decent flash drives have wear leveling plus under provisioning (i.e., spare blocks used to map out failing blocks) to extend the lifespan.

Modern OSes use delayed writes to avoid unnecessary wear, and flash memory technology has gotten better, so even budget flash media lasts longer than it used to. All else being equal, computers with less free memory available for disk caching will unfortunately result in more wear on storage media.

A few tips to reduce wear on flash media:

  • If possible, don’t use a journaling filesystem such as NTFS, ext3/ext4 and XFS unless it was also designed to handle flash media.
  • If not needed, disable last access time updates in the filesystem metadata (e.g., in Linux, use the “noatime” or “relatime” mount options ; Windows has a registry setting for NTFS).
  • Disable Windows ReadyBoost either for a specific USB flash drive or altogether (ReadyBoost is only automatically enabled when the Windows system drive isn’t stored on a SSD).

Syncthing creates a temp file for every file that’s being updated, so there can be a lot of writes. For most users it’s not an issue for a SSD, but USB flash drives might not be as reliable. It really depends on the frequency of writes and the size of the files.


Just a personal experience, but I’ve had a Samsung SD card die after a few months of using it as permanent storage for file synchronisaton :confused:. It was a standard SD card from the EVO series. Since then, I’ve only been using high endurance SD cards which sustain much more writes (e.g. the ones from Samsung use MLC flash memory). For example, I’ve got one from Sandisk in a Windows tablet, and it’s been running strong for 3+ years with Syncthing (and I did not optimise NTFS as described above even though I probably should :upside_down_face:).

You should still probably be fine as long as you don’t go crazy as I did, treating the flash memory basically the same way as normal SSD storage.


dang, yeah i have had something like that happen with a sd card and my 3d printer. The card corrupted after 3 months haha.

I probably will use Free-file-sync with one direction mirroring from the laptop to the flash drive. Then every 8 hours i will have free-file-sync compare the laptop to the usb drive and if files need to be updated, it will automatically do it.

or if i do use sync-thing, to make sure i set the parameters on the flash drive correctly.

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