Bitcoin Forum

My Bitcoin client is 20 weeks behind on the blockchain sync.

Anyone know how long it will take to sync?

It seems like it's just stuck even though it says I've got 17 connections.

If your running it on normal harddrives a good few hours at least. The shorter the time the longer it takes due to bitcoin having more and more transactions. It slow but it get there in the end

Thanks for that.

It's actually moved to 19 now so it's put my mind at rest.

Anyone know how big the blockchain is?

At this time, the blockchain is around 40 Gb. It will only get larger, so the more recent you are, the more data there is that Bitcoin Core needs to process.

40gb? Wowzer

What's the forecast for it's size in anther 3 years or so?

Are they working on a way to resolve this ridiculous sync time?

There are no workarounds for it, you need to download all the data and synchronize it up until the latest block. Some take weeks for them to complete that download. I'm thinking of compressing the blockchain data on a certain block, say at block number x, someone will archive the whole blockchain and put it online for others to download, though I'm not sure on how would that pan out.

It's hard to say. If the block size doesn't change, it could be well over 200, given that all blocks are full. It is a rough estimate and is inaccurate but technology should improve over time and it wouldn't be a huge concern.
The sync time depends on the CPU speed and HDD speed. Those are the two main bottlenecks. Internet speed isn't much of a problem due to the headers first synchronization allowing your peers to send you the blocks simultaneously. This also means that downloading it seperately online is not as efficient as before too!

Yeah, for future reference it takes anywhere from 1-Day-5-Days for the Core to fully catch-up.

20 weeks hmmmm with an average PC I'm guessing it should take around 10-12 hours. I've downloaded the full blockchain on a number of computers in my time & it usually works out as around 30 minutes for 1 weeks worth of blocks, sometimes more & sometimes less.

My machine is quite a high spec set up and 12 hours hasn't eve made a dent in it.

Don't know why but 30 mins per week of TX's isn't achievable for me.

How is the bandwith usage?

If you have a low bandwidth plan then I would suggest you to try installing MultiBit client (https://multibit.org/download.html) and transfer your bitcoins from previous, unsynced wallet.dat to your new client and let it sync. It actually takes less time to sync because it is a thin client (it does not download the full blockchain).

Thin clients do not validate transactions, they just assume that the longest blockchain only has valid transactions. Moreover, thin clients do not help the network. Instead, they rely on full nodes (like Bitcoin-Qt) to do the heavy lifting.

Now if you have a good bandwidth and want to contribute bitcoin by running a full 40GB node, then go ahead with Bitcoin-qt ;)

P.S There should have been a thread where bitcoiners, who want to use the newly downloaded core client, can seperately download the full blockchain in a compressed form (I think it can be compressed upto 20GB), unzip it, compile it with the client and then do the last syncing and most importantly, that file should be updated weekly. I think a legendary member should open a thread like that! Maybe theymos if you have time? :)

#0 If someone has a problem with their car, dont suggest they take the train. Its rude.

#1 multibit uses a different wallet format, you cant just take the wallet.dat, shove it into the Multibit directory and hope that its working.

#2 Multibit HD does not allow to import private keys. What you suggest is not possible at all. Even if you export every private key. If you are refering to multibit classic, you should link to it.


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40 GB is not enough.


There was a thread like that. Search for bootstrap.dat, but the blockchain can not be compressed to 20 GB, its roughly the same size when downloaded seperately. The problem however is that a seperate download can not be verified at the same time, thus it will take longer if you download the blockchain first and verify it later. Since 0.10. bitcoin core can download from several peers at once and should thus us the full bandwith available.