Bitcoin blockchain sync very slow on HDD

[broflof]

I'm syncing my Bitcoin wallet blockchain using latest Bitcoin Core on Linux.

It progresses very very slowly, right now 2 to 3 weeks in 12 hours.

CPU and net usage stay low most of the time, problem is not there (most likely). HDD usage is constant, I think that's probably the bottleneck. It's a 7200rpm standard desktop HDD.

10 years ago I could sync the blockchain on a slow 5400rpm laptop HDD without major issues.

Time to buy big SSD perhaps.

But the interesting question is,
Does syncing get harder over time as the blockchain gets longer?

Or has something happened to the protocol so it would be harder now?

Or has the code quality of Bitcoin Core gone down?


The GUI also stalls badly during sync. I don't remember when this problem began but it did not always exist.

Syncing monero is also extremely slow and it has been so as long as I can remember.  But that's another story.

[promise444c5]

In the last 10 years there're fewer transactions in a block... now there's  more.
Use the current version check the latest news section  of the forum for the torrent file,
Then if you are using bitcoin-qt GUI  check the dbcache increase it, it could make it sync process more  faster(note the value is in MB ) this should  be done carefully  in accordance  to your  ram  capacity .

Does syncing get harder over time as the blockchain gets longer?

Not really but yes and might depends on the hardware , people can still get it done in just 2~4 days.

The GUI also stalls badly during sync. I don't remember when this problem began but it did not always exist.

Sometimes when when block index is writing to disk you might experience  that and you would think it's just stall

[un_rank]

Does syncing get harder over time as the blockchain gets longer?

Or has something happened to the protocol so it would be harder now?

It should, but the chain is not increasing as such a rate that will cause an significant lag in download time. Could be from the internet connection.

Nothing happened on the protocol level to make it harder either.

- Jay -

[LoyceV]

CPU and net usage stay low most of the time, problem is not there (most likely). HDD usage is constant, I think that's probably the bottleneck. It's a 7200rpm standard desktop HDD.

You have 2 bottlenecks: RAM, and HDD speed. Both are more or less interchangeable: with 32 GB RAM and 12000 MB dbcache, your sync will go just fine. With 8 GB RAM and an SSD, the SSD is still the bottleneck. I tested both of these examples myself.

10 years ago I could sync the blockchain on a slow 5400rpm laptop HDD without major issues.

Ten years ago, the entire blockchain was only 20 GB.

Does syncing get harder over time as the blockchain gets longer?

Yes. The chainstate directory keeps growing, and requires more and more RAM (or a LOT of disk activity) to verify the download.

Or has the code quality of Bitcoin Core gone down?

Nope. Older versions were much slower to sync.

Syncing monero is also extremely slow and it has been so as long as I can remember.  But that's another story.

Monero is even more demanding than Bitcoin Core, despite a much smaller blockchain.

TL;DR: get an SSD.
If you have a small SSD, put the chainstate directory on it. That will make a huge difference for Bitcoin Core. If you don't have an SSD yet, buy one. Get a decent one for best performance. It's going to largely improve your entire computing experience.

[philipma1957]

a decent i5 gen cpu say i5 8500 or newer
a 1 tb samsung ssd or bigger
16gb ram or more
a decent internet connection say 100Mbps or more


if you have all of the above you will be under 1 day


obvious that

an i7 14700
a 2tb nvme2 quality ssd
64gb ram
and a 1Gbps internet

will be faster.

In fact the second setup may be faster than the offered download speed.

I have used 200Mbps and
128gb ram
1tb nvme2 ssd
threadripper cpu

My setup was able to do 190Mbps constantly which makes me suspect my internet connection was my bottle neck

I will soon get 1gb internet and try to see how fast I can do this.

[ABCbits]

Does syncing get harder over time as the blockchain gets longer?

Short answer, yes. Not only each block become bigger, total UTXO keep growing.

Edit: I assume "gets longer" refers to newer blocks.

Or has something happened to the protocol so it would be harder now?

AFAIK no. New stuff (such as SegWit) solve few problem including quadratic verification time.

Or has the code quality of Bitcoin Core gone down?

No. Jameson Lopp did benchmark which prove the opposite on https://blog.lopp.net/bitcoin-core-performance-evolution/.

The GUI also stalls badly during sync. I don't remember when this problem began but it did not always exist.

That's true, it's known issue for few years. See this issue, https://github.com/bitcoin-core/gui/issues/299.

[broflof]

Thank you, for answers.

Finally, actually, I got "pro level" answers instead of just "works fine for me", "can u show ur logfiles", "just get SSD bruh". 

I got a cheap RAM upgrade, set dbcache to 16GB (was 4GB or 6GB), started syncing.

At some point the GUI had stalled very badly, I could do nothing so I shut down Bitcoin-qt and it shut down cleanly. When I restarted it the blockchain was in fully synced state. So my remaining 5 weeks were synced in 2 to 3 hours, much faster than before.

I don't know if the GUI would have recovered if I had waited for some more time. Maybe I tried to use it just at the critical moment. It's unknown for now.


Monero did not get faster than before and the last 50000 to 100000 blocks seem to be much slower than anything before. I didn't find any option similar to dbcache in Bitcoin. 600 blocks/h is the speed now. Used to be 2200 blocks/h for quite long. I benchmarked different file systems and certain types were occasionally faster than that but fell to the same slow level at some point.

Maybe it's SSD time next.

[larry_vw_1955]

In fact the second setup may be faster than the offered download speed.

I have used 200Mbps and
128gb ram
1tb nvme2 ssd
threadripper cpu

My setup was able to do 190Mbps constantly which makes me suspect my internet connection was my bottle neck

I will soon get 1gb internet and try to see how fast I can do this.

how much did that setup cost you? i'm guessing around $2500. most people would be better off just buying bitcoin instead of trying to spend that money to download the blockchain. it's just going to be an ever increasing game of having to throw more and more hardware at the problem big waste of money unless you just have that stuff lying around from something else...

[LoyceV]

Monero did not get faster than before and the last 50000 to 100000 blocks seem to be much slower than anything before. I didn't find any option similar to dbcache in Bitcoin. 600 blocks/h is the speed now. Used to be 2200 blocks/h for quite long. I benchmarked different file systems and certain types were occasionally faster than that but fell to the same slow level at some point.

Maybe it's SSD time next.

Last time I synced Monero (on a server with 32 GB RAM, and HDD), the first thing it told me was to get a SSD. I couldn't do that, and eventually removed Monero because even after it was synced, the entire server felt "sluggish" while it was running.

[ABCbits]

At some point the GUI had stalled very badly, I could do nothing so I shut down Bitcoin-qt and it shut down cleanly. When I restarted it the blockchain was in fully synced state. So my remaining 5 weeks were synced in 2 to 3 hours, much faster than before.

I don't know if the GUI would have recovered if I had waited for some more time. Maybe I tried to use it just at the critical moment. It's unknown for now.

Based on my experience, the GUI would be responsive again and show latest information. Although if you need to know latest sync progress, you could open debug.log and look for newest line which contain text "UpdateTip".

Monero did not get faster than before and the last 50000 to 100000 blocks seem to be much slower than anything before. I didn't find any option similar to dbcache in Bitcoin. 600 blocks/h is the speed now. Used to be 2200 blocks/h for quite long. I benchmarked different file systems and certain types were occasionally faster than that but fell to the same slow level at some point.

Maybe it's SSD time next.

There are other parameter you could try, such as --block-sync-size, --fast-block-sync and --db-sync-mode. If you have question specifically about Monero, you should create new thread/reply on different board.

[kevinteohuiwei]

I just got mine sync and its 660GB .... done in 5 days with a 3MBPS line on my phone data.
Just 16gb amd ryzen 9 7950 and 1tb ssd ext drive.

Yea, i did set the cache to 1800MB compare to originally 450MB. It does help. Even on my raspberry pi 5, i did sync it within 5 days on the same ext drive.

same core version 27.0. I think it could be the cache 450MB default setting. Try changing it and trying different setting. Hope it helps.

[BlackHatCoiner]

Does syncing get harder over time as the blockchain gets longer?

It depends on the transactions. If the future transactions create more UTXO than spend, then it will be worse over time, yes.

Or has the code quality of Bitcoin Core gone down?

I believe it's just your HDD. It's extremely slow to download and index all that information on an HDD. Have you tried SSD?

Short answer, yes. Not only each block become bigger, total UTXO keep growing.

How do you know that the UTXO keeps growing? Are there stats that support this?

[LoyceV]

How do you know that the UTXO keeps growing? Are there stats that support this?

I don't keep track of UTXOs, but I have data on funded addresses. Apart from small temporary reductions (usually due to consolidation at low fees), they're generally growing in number.
The way I see it: Bitcoin gets more expensive, and more people own smaller and smaller bits of it.