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what is sync

  • 14 replies
  • 1 has this problem
  • Last reply by cor-el

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Well, I've been doing Firefox sync for a long time, and it seems to work pretty well. But I'm a little confused. What EXACTLY is going on? Note: I do NOT want to know how to set up sync. I know that.

First question. When sync is automatic, when exactly does it do it? I pull down and do "Open menu" with the three bars, and then hover over the sync arrows-in-the round. It might say "Last sync: 5 minutes ago", and it might say "Last sync: 5 seconds ago". Nothing happened on my Firefox five seconds ago or five minutes ago. So who told it to sync? What determines when it is supposed to sync? I presume Firefox automatically does a sync if you change a bookmark or password.

Second question. What exactly is a sync? I gather that if the sync file (containing bookmarks and everything) in the cloud is younger than the local sync file, the local sync file will be replaced by the one in the cloud. If the sync file in the cloud is older than the local sync file, that sync file in the cloud is replaced by the local one. Is that what's going on? That is, it's all about the time stamp? Do not tell me "Sync lets you share all of your data and preferences (such as your bookmarks, history, passwords, open tabs and installed add-ons) across all your devices." I know that.

Third question. Let's suppose I want sync to ONLY be manual. As in, it will ONLY sync when I do Tools>Sync Now. How do I set it up for that?

All Replies (14)

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I think its weave , also you can type "about:config" without quotes on your search bar get an insight.

Keep up the curiosity

Modified by binaryninja

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Give me a break. That doesn't answer ANY of my questions. Did you read them? No, didn't think so.

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do you want know how sync actually works,

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Read my questions. Please post if you have answers. Don't bother to troll. The Wikipedia article doesn't come close to answering them, and about:config is a Firefox configuration manager. I know all about that. No insight there.

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My questions had nothing to do with security. I have a lot of confidence in FF sync encryption.

I asked specific questions. Hint - look for the question marks.

Modified by user700204

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There are services.sync.scheduler prefs that you can find on the about:config page.

When a Sync is done then Firefox checks with the server what changes have been occurred to engines enabled for Sync and this data will be uploaded to the Sync server. You can't set Firefox to only do a manual Sync apart from disconnecting from Sync and only connect when you intend to Sync. I don't know if this gives side effects because this might be seen as an initial Sync.

You can open about:sync-log via the location bar to see what Sync logs are available. You can temporarily toggle this pref to true to create a Sync log in case of success to check how Sync performs.

  • services.sync.log.appender.file.logOnSuccess = true

Do not forget to reset services.sync.log.appender.file.logOnSuccess after you are done testing.

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

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Thank you. I know about, and am comfortable with, about:config.

My idletime is set to 300 My idleinterval is set to 3600 My singleDeviceInterval is set to 3600 My activeinterval is set to 300

Are these supposed to be telling me how often a sync happens? Are these seconds? Does a sync happen automatically after a certain amount of time? Does a sync happen when I make a change to my bookmarks or login passwords?

So what is "Sync Now" for?

My sync-log contains a hundred or so small files that look like this - error-sync-1545876186087.txt going back a week or so. Whazzat?

Modified by user700204

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Those are the default values when Firefox checks with the Sync server and yes the times are in seconds (3600 = one hour). When you make changes to one of the enabled engines like a bookmark then Firefox can sync more often.

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So, my Firefox is set to sync automatically every 3600 seconds, and will also do it whenever I make a change to an "enabled engine"?

Also, what exactly happens in a Sync? My local system values are copied to the sync server IF they are more recent than the ones up there? Or, the server values are copied to my local system if the ones on my local system are older? That is, the direction of the copy depends on the date stamps of the sync files?

Sorry, this is just a little confusing.

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Data from each device is uploaded to the server and data from other connected devices is downloaded to your computer, so eventually all devices get the same data. There is no master device.

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If you are interested in technical details, see;

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Wow, that Github article is pretty complete. BUT, I don't think it answered my questions. Is it true that when a machine connects to the server and "syncs", what happens depends on the date stamps on the server sync file and the local sync file? That is, how does sync know to update my computer by downloading a sync file, or instead to be updated BY my computer by uploading my sync file? That is, the most recent file is the one that is shared.

So if I move to a new machine, and start playing with bookmarks there, before a sync happens, it isn't really clear that everything will be preserved. Seems to me that if I move to a new machine, I have to make sure that Firefox on that machine is sync'ed before I start making changes to it.

Also, is my system up to automatically sync every 6 minutes?

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If you look at a success Sync log like I posted above then you can see a record of what Firefox is doing.