Dht Question In Sync. Private Files Or Worldwide Files?²

[BeTheSync]

Hi all,

(because my initial topic was hijacked and got confusing, I'd like to ask my initial question again, because I'm not realy sure, if I understand DHT with BTSYNC.)

 

It would be nice, if somebody could try to explain it again, or point to a link I can refer.

 

Thank you.

 

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Initial Question:

 

is the somewhere in the world wide internet, a (german language) document/page/site, which I can refer to understand how all the DHT thing is working within btsync?

 

I read some about it, but I'm really not sure, if I understand while using btsync on 3 different machines (mac/unix/win) only for my private backup/sync pleasure. ;-)

 

I'm interested in the following:

 

Is DHT good or bad (and can it flip in special cases?) for only sycning my own private files (which nobody else in the world has a dupe from).

 

And how does it look like, when most of the files, I sync between my private machines, are files that a lot of other btsync User might also have on their sync-servers, like documents from the web or something else (yt-videos, free mp3, images from wikipedia...)

 

Thank you very much for linking me :-)

 

 

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Assuming your computers are connecting to each other already, adding DHT won't give you any benefits.
Individual files are not shared.
Entire directories are.
The files synchronized in your secret are NOT synchronized to computers that don't have your secret.

Thank you Harold,
this helps to understand the sharing part, I guess.

So a useful situation for DHT would be, if I had an additional folder, which I would like to share with any machine who knows my secret and is not one of my own machines? Still dont understand the benefits of DHT inside btsync.

[Guest proactiveservices]

Hi,

 

Information on DHT (in German) is not difficult to find. Please try looking for it before asking: http://de.wikipedia.org/wiki/Verteilte_Hashtabelle

 

My understanding is that DHT is useful in the following scenarios:

Scenario 1:

Peer 1 is has data to share. It queries tracker X and retrieves a list of peers P. It uses DHT.

The list P contains peers 1 through 15.

 

Peer 16 has the same data to share. It queries a different tracker - Y - and retrieves a different list of peers, Q. It also uses DHT.

The list Q contains peers 15 through 30.

 

Both peers may suffer as they don't have all of the available peers. Peer 1 only knows P and peer 16 only knows Q.

However, helpful peer 15 knows both lists - P and Q, and shares this list to peer 1 and 16 via the DHT. Peer 1 and 16 then share this list amongst P and Q, and the swarm is effectively connected together.

 

Scenario 2:

Peers 1 through 100 have data to share. They use tracker X to maintain a list of peers and use DHT.

Peer 45 goes to sleep, and remembers the list of peers 1-100.

Whilst peer 45 is asleep, peers 101-200 join the swarm.

Tracker X fails as someone spilled coffee on the server. There is no longer a central tracker.

Peer 45 wakes up and cannot talk to tracker X. Peer 45 queries its previous peers 1-100 via the DHT. These peers share information about peers 101-200 and peer 45 can rejoin the larger swarm.

 

Corrections welcomed (or comments saying I don't know what I'm talking about ;-)

[piotrnik]

From what I understand, for BTSync, DHT would mainly function as another way for the computers to find each other if you haven't pre-defined connections.  You are correct that if they can see each other via pre-defined connections, DHT effectively does nothing. 

I believe DHT functions as a tracker in traditional BT, since there is no central tracker for BTSync.

[Guest proactiveservices]

BitTorrent Sync does use centralised tracker(s). Hence the "Use tracker" property item, and why DHT is optional and disabled by default. I believe the use of other trackers is pretty high up the "requested features" list :-)

[BeTheSync]

Thank you Guys,

the several scenarios helped much!

those examples are what is always very useful for unexperienced users like me.

A Document about a matter is a nice thing, but it needs to connect to my-reality using the software :-)

Thanks again.