Bitcoin Forum

So I decided to try downloading the blockchain on a normal ADSL connection (20mb line, supposedly). I'm nearing the end of my first week of downloading 24/7 and I still don't have the whole thing yet. I've even added some of the most well connected nodes.

It's an academic exercise of course, I know I could torrent the thing first, but wow- that blockchain.

The main choke point of blockchain sync speed is your hdd not your internet speed.  If you have a solid state drive and/or a RAID array it will dramatically decrease your blockchain sync time.  You can also add dbcache="number_of_mb_of_RAM_to_use" to bitcoin.conf to decrease the strain on your hdd while syncing.

P.S. Default value for dbcache is 25 and a good value for a computer with 4gb ram is 3000, assuming you aren't doing anything RAM intensive.

So why are you posting this in technical support? You don't need support so stop crying wolf. Hell, why are you posting this at all? Anyone moderately interested in bitcoin should know the blockchain is 10gb.

You might wanna try this one : https://bitcointalk.org/index.php?topic=145386.0
Or maybe wait for the next update, august 30 is pretty old, already.

EDIT : Ok, read too fast. You knew... Then you're not asking for help, just switch to fiber. ;D

The box I am using has 512MB of ram, :-) I found it on the street and was curious to see how bare-bones a node could run. Pentium duel core. I'll get more stats when it's finished and I check out the bios. I didn't know however that RAM influenced the download, but now I see.

After the initial verification, it should be fine.  Well, fine-ish.

I have two nodes running on an old Athlon XP 1800+ with 883 MB reported memory.  It runs fine most of the time, but bogs down a bit when the network is growing quickly and blocks come too fast, or when feeding a newly started node.  A single node, or even a dual that disallows incoming connections, would probably be fine.

While the bottleneck is certainly in your machine, the speed of your first peer can also be a factor for faster machines.  I also run some diskless nodes that maintain the entire datadir in a RAM drive.  While I haven't done any scientific measurements, just by watching the logs it is obvious how much faster the RAMdisk node is when feeding a new node's initial block download.

Strange I bootstrapped a node from genesis block to current in less than 18 hours.  :)  As others have pointed out sufficient memory (bitcoind doesn't seem to use >2GB regardless of available resources) and fast disks are far more important than bandwidth speed.   I think you will find if you monitor your network connectivity your average download speed is nowhere near the linespeed of your ASDL connection (20Mbps = 9GB per hour).

Slowness these days is mostly due to cruddy peers combined with bitcoin's poor handling of cruddy peers. The work in progress for 0.9 (headers first) improves this enormously. (e.g. down to a couple of hours on my DSL test)

I've had success killing and restarting bitcoind until I'm syncing from a fast peer (maxing out my bandwidth). I know others have had success using -connect using an IP in a known-to-be-fast range (e.g, if you're bootstrapping on AWS, dig the DNS seed until you find a peer with an AWS IP). Sync time goes down to less than a day even with a spinning metal disk.

Guys, u r talking about USA and high-end computer users. What about the rest of the world?

The point is that the OP was not maxing out his bandwidth. It is possible to use your full bandwidth to download the blockchain, if you're selective about what peers you connect to, no matter where in the world you are connecting from. In 0.9 this manual tweaking should no longer be needed.

The main choke point of most long downloads is ISP's they dont like this kind of traffic as it stresses there network more than normal web browising and it makes them cry....

hell old IDE drives have higher read writes than your bandwidth RAM isnt a problem CPU isnt a problem....

my recommendation is if your struggling rent or sign up for a VPN for a day or 2
took me less than a day to download the entire blockchain on my 12mbps line :) (my ISP dosnt care what kind of traffic you use)
a VPN stop your ISPs from slowing down or thottleing you connection speed as easy

It's not streamed reads, but random reads over a multi-gigabyte dataset. Spinning metal disks are notoriously bad at that.