How can I keep folders synchronized between several machines over my home network?

Question

Like many people I take quite a few photos, and also like quite a few people I don't back up as frequently as I should.

What I'd like to be able to do is automatically synchronize my "to be backed up" folder to some of the other machines that live on my home network.

I need something that:

• Doesn't require anyone to be logged on
• Monitors folders and doesn't require a manual start
• Only sends across what has changed
• Doesn't force traffic over an Internet connection (The initial sync may be several gigabytes)
• Isn't limited beyond local available disk space (EDIT: For the sake of argument, assume there is in excess of 50 Gb that I'd like to float around.)
• Copes if "the other end" goes away unexpectedly, is not available (for instance, If I've taken my laptop to see my parents, I obviously won't be able to see my desktop PC)

Is anyone aware of anything that fits the bill? I've come close, with things like Windows Live Mesh (but that is both limited in quantity, and requires me to be logged on at both ends for the sync to er, sync), but I want to evaluate the options before sitting down and developing something myself if needs be.

Does anyone know of anything that fits my requirements?

Answer 1

You're asking for a lot.

Since internet syncing is out, you can't go Dropbox which is what I would have voted for.

You could take a look at SyncToy, since from your tagging I'm assuming you are on Windows. It is free from Microsoft.

However, this MAY not fulfill your demand of "not being logged on". I am not quite sure how to interpret this. SyncToy does not work when you are not logged on on the machine that requires a sync. However, it can pull data form unattended machines (as long as these give access to the protocols that SyncToy uses.

SyncToy has worked for me and for my friends in the past. I am not currently using it, because I switched to a Mac.

Update: from Windows users, I also hear good stories about SyncBack, which offers a free version.

Answer 2

The options from Microsoft are Windows Live Foldershare and Live Mesh. Both are under development.

I used to use foldershare and found it quite snappy and reliable.

I currently use Live Mesh. It (currently) offers 5gb of cloud storage, and I use it day to day between 4 computers. It also allows you to remote desktop between computers through firewalls, and sharing folders with other users of the service.

To answer your points though, with Live Mesh:

• You need to be logged on
• Monitors folders
• Only copies changes
• Uses local connections when possible
• Doesn't care if there's no machine on the other end. Can use cloud storage at the same time

Answer 3

SyncBack is so good it deserves its own answer :)

I think it meets all your requirements. Almost. I'm not only sure if it fits Isn't limited beyond local available disk space. What do you mean by this?

Answer 4

Fairly new on the market (as in it's still in Alpha) is BTSync. It ticks a surprising number of the items on your list and is still under development so more items could well be sorted.

• The ability to run BTSync as a service is something that is under development.
• Automatically checks the directories for changes
• Chunks the file into 4mb sections and only sends across those that have changed (although this algorithm needs some improvement as it doesn't do a differential copy)
• Uses LAN transfer whenever possible. Only goes via Internet if it needs to and also supports using relay servers if a direct connection isn't possible.
• Doesn't actually support cloud storage so only limited by your disk (although memory usage is high for a large number of files currently).
• Copes with handling changes in folders happening offline. Doesn't merge files automatically.

It also supports a bittorrent-style method of distribution, so adding a new node will download from all of the existing nodes, and supports having read-only shares, so that a true-backup style solution can be created.

Answer 5

I've just remembered ViceVersa

I use it to sync my local development code with my virtual server so I don't have to keep publishing. It runs on a single PC and can monitor multiple folders and syncs them when it detects a change or on a schedule.

• It can run as a service so no one needs to be logged in.
• It monitors the folders for changes
• It only syncs the new files
• It runs on the LAN
• The Pro version can sync opened files (such as Outlook.pst)

I would install it on the Desktop PC so that it runs whether the Laptop is there or not.

It does cost but there is a free 30 trial.

Answer 6

I would like to propose a new opensource tool called Syncthing, which is very simple to setup and works over any connection setup (wifi, ethernet, LAN, WAN/Internet) and devices (from computers to smartphones).

I tried it to synchronize my smartphones and my home computer over Wifi, plus my home computer with my work computer over internet, and this all worked nicely.

The only drawback is that both devices you want to synchronize must be turned on during the synchronization, but this is also an advantage because this is due to the fact that there is no middle-man server like Dropbox (no eavesdropping).

Answer 7

Dropbox

• http://www.getdropbox.com/
• for Windows, Mac, and Linux

Answer 8

I use an app called GBridge for a couple things. It creates a VPN and allows local access to PC's even if they're not on the LAN.

I use it for Remove Desktop (well... VNC) from just about anywhere and I have shared folders that auto-sync (on a schedule)

The only downside is that the whole program is a little rough around the edges sometimes..but free apps often are.

I like that it's not server based at all, it just uses google's authentication system not for file transfers.

Data will remain on the LAN if the machines are both local, and use the internet only if needed.

I think the only way GBridge fails to meet your qualifications is that I'm not sure about the login requirements.

Answer 9

Another very good alternative is Sugar Sync, with a free 5GB account.

Sugar Sync is really efficient with transferring large files between computers. I have tried the other alternatives as well but this one is the best among them.

Answer 10

A small Network Attached Storage device (NAS) with four identical disks (for RAID 5) would seem to be your ideal solution. A NAS is essentially a small low-powered server dedicated to serving disk shares. Multiple clients can use the shares at once. Synchronisation happens as quickly as the clients' operating systems allow.

• A NAS doesn't require anyone to be logged in.
• It is available continuously, thus doesn't require a manual start, and with RAID 5 you get some resilience against hardware failure.
• Delta compression really depends on the application you're using. I expect it's possible since a NAS just presents as a disk.
• Only uses an internal network connection, not Internet.
• No limitations beyond disk space.
• If you take your laptop to ma's, the operating system should cope just fine after the initial "Whuh? Where'd my disk go?" shock. In my experience, it takes Windows a little longer to calm down than Linux.

It's not especially cheap:

1 x NAS @ £146.88 = £146.88

4 x 4TB NAS drive £199.99 = £799.96

That's nearly £1000 all told.

But with RAID 5 that gives you 3 x 4TB = 12TB of disk space, which I guess should keep you going for a while?

Answer 11

i use DropBox

it creates a special folder in your documents folder which you can save directly to. it will then sync online and to other computers setup with the same account.

you can set it up to start on startup and it remembers your login details so you don't need to re-enter them each time.

There is a free version which is 2GB.

I'm not sure about the other requirements but it is definitely easy to use and also has the bonus of a public folder that you can use to share files publicly.

Hope that helps,

Josh

Answer 12

Haven't researched this very much at all, but use Jungle Disk for our digital images. Both as an off-site (cloudbased) backup of them, and as a way of accessing them from multiple machines: just set a large local cache and photos you accessed earlier will be on your local disk.