Syncthing alternatives
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That's really weird. I've been using it for mobile-desktop-server-offsite sync for many years, with transfer sizes over 15TB, over WiFi, cellular, cable, fiber. I've never seen data corruption. Conflicts, sometimes. Permission issues, sometimes. Wiping something accidentally, sometimes. It's even more weird because Syncthing performs computes hash values for the files it manages. I don't know if it performs hash validation after copying remotely but if not, it can be forced manually which would tell you what's fucked and be pulled from the source, if it still exists.
Nevermind, it verifies the result:
When a block is copied or received from another device, its SHA256 hash is computed and compared with the expected value. If it matches the block is written to a temporary copy of the file, otherwise it is discarded and Syncthing tries to find another source for the block.
According to this, if you have data corruption it can only occur between copying/moving a temporary file on your destination to another directory, or it could occur on the source itself. Both of those scenarios are a cause of concern and would likely persist with any utility. Moving or copying a file from one location to another on a sane machine should not corrupt it. If I were you I'd ensure my server doesn't eat bits. If not the storage media, it could be bit rot, or bad RAM.
Just in case everything seems fine, let me tell you what I dealt with. I had a Ryzen 5950X machine with 32GB of RAM. It worked well since inception with no signs of RAM or data corruption issues. I test every new machine with Memtest86+. At some point I migrated the storage from Ext4 on LVMRAID to ZFS. All good. Then I wrote an alarm for Prometheus to tell me if there's any issues in ZFS. A week later I get an email about a ZFS error. I check the system - says checksum errors, data has been corrected, applications unaffected, run a scrub to clear. I ran a scrub. A few more checksum errors found, all corrected, we're clean now. There was a strong solar storm around that time, probably that. A couple of weeks later I get another email. Same symptoms, same procedure. No solar storm. Shit. Memtest86+ - pass. Hm. A couple of weeks later I get another. Same thing. Memtest again - nothing. This went on for several months. Meanwhile the off-site backup sees nothing like that. While running Memtest on another machine I noticed that the test passes following the first took longer than the first, a lot longer. I thought something might be wrong with that machine. Dug into it, got into Memtest's source code and discovered that the first pass is shorter on purpose so that it quickly flags obviously bad RAM. Apparently if you want to detect less obvious issues, you have to run multiple passes. OK. Memtest the main server again, pass 1: OK, pass 2: OK, pass 3: OK, pass 4: FAIL. FUCK. Memtest each stick separately for 4 passes: OK. Memtest 2 at a time: OK. Memtest all 4: FAIL. Alright, now we know why ZFS keeps finding checksum errors. Long story short, this machine could not run this RAM in 4-DIMM config. Replaced it with another RAM that's rated to run in 4-DIMM config on that processor. No more checksum issues. If I was running the older Ext4-on-LVMRAID storage stack, I would have caught NONE of these and it would have happily corrupted files here and there. In fact it likely did and I have some corruption. Moral of the story - run many Memtest passes and use checksumming storage stack like ZFS or Btrfs. I strongly recommend ZFS since its stripe RAID works fine unlike Btrfs'es. If you don't find bad RAM, start using it today, even if you're working with a single disk and add redundancy when you can. Only after change Syncthing for something else if you still somehow get corruption without ZFS'es knowledge. And if ZFS tells you that you have checksum errors, you likely have bad hardware.
This post doesn't benefit me at all but I love how long it is.
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Hi,
As the title suggests: what are alternatives to syncthing that are basically fire and forget, works on multiple device types, and just focuses on file syncing?
I've had over the months the weirdest problems with syncthing, and lately I noticed some of my photos got corrupted, which is an absolute no no for me. I use syncthing currently as a easy automatic backup of documents, photos and other files, between my PCs and my phones (they all send only to the server. Folders are not shared with other devices).
wrote on last edited by [email protected]Is Syncthing my ideal backup application?¶
No. Syncthing is not a great backup application because all changes to your files (modifications, deletions, etc.) will be propagated to all your devices. You can enable versioning, but we encourage you to use other tools to keep your data safe from your (or our) mistakes.
https://docs.syncthing.net/users/faq.html#is-syncthing-my-ideal-backup-application
Sync is sync. Sync is NOT backup.
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Crazy, thought for sure it would fail testing.
Still wouldn't trust it personally after a failed stick from a matched pair regardless of what the test says though.
wrote on last edited by [email protected]Yeah. But it could be the board that burned it. But yeah, dead RAM is bad news, something is likely up. If I had data corruption and RAM didn't show errors I'd begin swapping components. If the machine is cheap and swapping components would be too expensive or impractical, I'd swap the machine for another, like a cheap second hand Dell box.
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Finished an all nighter memtest with a total of 12 passes. All good on the ram side
wrote on last edited by [email protected]Condolences, you just switched to Ultra-Violence.
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This post doesn't benefit me at all but I love how long it is.
wrote on last edited by [email protected]Let me tell you about diagnosing a reproducible crash on that 5950X system after swapping the RAM with verified good modules. An issue I only discovered because I decided to warm myself using Folding@home for a couple of cold days while my building was switching the central heating on.
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Could be a bad AP.
I once had a switch with a failing power supply that would corrupt MP3 artwork when writing to the MP3. That was a weird one to track down.
That sounds like a crazy story to find out what the issue was. As I stated somewhere on the thread, ram is not the issue, and the APS are quite new (Aruba stuff that is 1 and a half year old). And the only situation I get this issues is with my phones in specific. I will probably use the smb solution stated before and see how is goes. If the thing still happens, then is hunting time
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Yea, gotta be something odd with your setup.
Currently I have one phone (of several) thats syncing en excess of 10,000 files, some only on Wifi (with 3 access points), some wifi/cell data.
ST knows the state of a file, so a disconnect should have no effect. If you're getting corrupted files, I wonder if something else is going on which may also affect another sync tool.
Try Resilio for the same folders, see if you have the same problem (disable Syncthing of course, otherwise conflicting edits will cause file corruption).
I checked their page and I have now a personal license. I am going later to try to find out how it works, so we will see
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Dug into it, got into Memtest’s source code and discovered that the first pass is shorter on purpose so that it quickly flags obviously bad RAM. Apparently if you want to detect less obvious issues, you have to run multiple passes.
I thought it was common knowledge that Memtest needed to be run for multiple passes to truly verify there are no issues. Seems that's one of those things that stopped being passed down in the community over the years. Back when I was first learning about overclocking around 2005 that was emphasized HEAVILY, with the recommendation to run it at least overnight, and a minimum of 10 passes.
The software should inform the user to run atleast 10 passes in the UI
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That sounds like a crazy story to find out what the issue was. As I stated somewhere on the thread, ram is not the issue, and the APS are quite new (Aruba stuff that is 1 and a half year old). And the only situation I get this issues is with my phones in specific. I will probably use the smb solution stated before and see how is goes. If the thing still happens, then is hunting time
Good hunting
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Is Syncthing my ideal backup application?¶
No. Syncthing is not a great backup application because all changes to your files (modifications, deletions, etc.) will be propagated to all your devices. You can enable versioning, but we encourage you to use other tools to keep your data safe from your (or our) mistakes.
https://docs.syncthing.net/users/faq.html#is-syncthing-my-ideal-backup-application
Sync is sync. Sync is NOT backup.
Would syncing your backup directory work? Like take snapshots of your system, dump the snapshots all in a single directory, and sync it to an off-site location?
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Would syncing your backup directory work? Like take snapshots of your system, dump the snapshots all in a single directory, and sync it to an off-site location?
No, re-read above.
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Would syncing your backup directory work? Like take snapshots of your system, dump the snapshots all in a single directory, and sync it to an off-site location?
Kind of. That improves your backup safety, but doesn't mitigate all the risks. E.g. if you accidentally delete everything from your backup directory, then all those deletions also happen on the sync'd one.
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I am using rsync triggered by cronjobs for this task now for... well... nearly forever.
If you ask Syncthing how to do local sync (e.g. to an external HDD), the answer is, use the right tool for the job: Unison.
If you ask Unison how to do certain things (directory timestamps is the one I miss), the answer is, use the right tool for the job: rsync.
In the end, it all comes down to rsync.
P.S. I'm actually gradually migrating up the chain from rsync, having used my own hand-built utility to make convenient rsync commands, but now using syncthing and Unison more.
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First and foremost Syncthing is not a 'backup' utility. Using it for backup is not at all recommended. Especially if you are dealing with Android or Raspberry pi, because the way clock / time works in these systems are pretty weird and create sync conflicts. So don't.
Now to the solution. For backup, use a proper backup solution like Kopia. Modern solutions support browsing the snapshots created as backups. Also creating periodic snapshots ensures better redundancy and better chance for disaster recovery.
Now if you will not use it for backup, take a look at 'Round Sync' available in F-Droid. It's an application built around the execptionally good app, 'rclone'. It is some what similar to Syncthing, but designed in a very different way. Also it is more difficult to configure to copy the files to PC.
I also wanted to mention that I have used Syncthing for many heavy lifting jobs and never faced issues with it. It is a feature complete app, with the philosophy of doing only one thing and doing it perfectly. So if you run into any issues, do reach out to forums or devs. They will definitely help you.
Curious about your point about time conflicts. Doesn't syncthing look at the change on your machine compared to the 'canonical' list also stored on your machine? So even if the timestamp is different, syncthing still detects the change, and the only problem is if the file is simultaneously modified on another machine before being propagated - which would be a conflict anyway.
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Hi,
As the title suggests: what are alternatives to syncthing that are basically fire and forget, works on multiple device types, and just focuses on file syncing?
I've had over the months the weirdest problems with syncthing, and lately I noticed some of my photos got corrupted, which is an absolute no no for me. I use syncthing currently as a easy automatic backup of documents, photos and other files, between my PCs and my phones (they all send only to the server. Folders are not shared with other devices).
I had some similar and obscure corruption issues that wound up being a symptom of failing ram in a main server node. After that, only issues have been conflicts. So I'd suggest checking hardware health in addition to the ideas about backups vs sync.
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Is Syncthing my ideal backup application?¶
No. Syncthing is not a great backup application because all changes to your files (modifications, deletions, etc.) will be propagated to all your devices. You can enable versioning, but we encourage you to use other tools to keep your data safe from your (or our) mistakes.
https://docs.syncthing.net/users/faq.html#is-syncthing-my-ideal-backup-application
Sync is sync. Sync is NOT backup.
This is why you should have file history versioning on. With backup this is a most.
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Curious about your point about time conflicts. Doesn't syncthing look at the change on your machine compared to the 'canonical' list also stored on your machine? So even if the timestamp is different, syncthing still detects the change, and the only problem is if the file is simultaneously modified on another machine before being propagated - which would be a conflict anyway.
It didn't work like that for me. I must admit I didn't dig deep to clearly see what is the problem. So my setup had a Windows Pc, a Raspberry Pi 5, and an Android phone, sharing a folder which had notes.
Whenever I save any changes in Windows machine, the android used gets updated without much issue, but the Raspberry Pi caused conflicts. When looked at the time stamps they were different and it looked to me like the Raspberry Pi 5 Syncthing is sending the old file as new one, because of the save time.
It read somewhere the issue is with how time is handled in Rasberry Pi. So I disabled the Raspberry Pi Syncthing and went on, because that was not really needed.
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It didn't work like that for me. I must admit I didn't dig deep to clearly see what is the problem. So my setup had a Windows Pc, a Raspberry Pi 5, and an Android phone, sharing a folder which had notes.
Whenever I save any changes in Windows machine, the android used gets updated without much issue, but the Raspberry Pi caused conflicts. When looked at the time stamps they were different and it looked to me like the Raspberry Pi 5 Syncthing is sending the old file as new one, because of the save time.
It read somewhere the issue is with how time is handled in Rasberry Pi. So I disabled the Raspberry Pi Syncthing and went on, because that was not really needed.
Huh, interesting. I'll bear that in mind - I don't like the idea of a system clock error causing an old file to overwrite a new one!
