Bitcoin-core syncing gets slower and slower

Services Support
21

Just wanted to share an update — I followed the guide from Start9: Start9 | Blockchain Migration, but instead of copying only the chainstate and blocks folders, I also included the indexes folder.

I copied everything from a fully synced Bitcoin Knots node running on macOS, and it worked perfectly.

The entire process, including the data transfer and setup, took less than a day. After restarting Bitcoin Knots service with the copied data, it resumed syncing immediately and at full speed — no more delays or sluggish block validation.

This method saved me a ton of time and frustration. Highly recommend it if you’re stuck with slow sync speeds.

2 Likes
22

It seems like the guide is written to transfer from Start9 to Start9. How were you able to do it from your Mac to start9? I want to do the same but just not 100% what needs to be done differently for Mac to start9

23

Once you’ve set up your SSH key so you can access your Start9 server, you need to run the following command in your terminal from the folder where your node’s data is stored on your Mac:

rsync -e "ssh -i ~/.ssh/{your-ssh-key}" -povgr --progress --append --rsync-path="sudo rsync" ./{blocks,chainstate,indexes} start9@{your-server}.local:/embassy-data/package-data/volumes/bitcoind/data/main

It’s important that your Start9 node is completely clean before running this. Make sure there is nothing inside the folders you’re going to sync to.

After the transfer completes, I had to update the permissions only on the folders that were copied so they have the correct ownership on the Start9 server. You can do that with:

sudo -i
sudo chown -R root:root /embassy-data/package-data/volumes/bitcoind/data/main/blocks
sudo chown -R root:root /embassy-data/package-data/volumes/bitcoind/data/main/chainstate
sudo chown -R root:root /embassy-data/package-data/volumes/bitcoind/data/main/indexes
24

Thank you for the quick response. If my IBD doesn’t make any progress in the next week I’ll give this a try. Does it need to be a fresh Start9 node or do you think uninstalling then reinstalling Knots would be sufficient?

25

Reinstalling Knots is enough.

26

Just an update in April of 2026 from the OP: We installed start9 v0.4.0 beta and retried a full bitcoin core sync on the very same machine. Unfortunately, the problem persists. Syncing works at first, after around a day or two syncing becomes exponentially slower. After more than 2 days we are down to ~2 blocks per minute an more than 100.000 blocks to. Provided the sync would not get slower, this would take more than 30days.

2 Likes
27

What version, and edition of Bitcoin are you running?

28

I am experiencing the same problem. I actually come from Umbrel. With Umbrel I was able to sync the blockchain and build an Electrum database within 26hours. It was really fast.

After seeing some video’s about the architecture of Umbrel and Start9, I decided to switch. I formatted the NVME and replaced the OS. My system is an N150 with 16GB memory and 2TB nvme SSD.

I am really confused about the fact that Start9 is so much slower than Umbrel in the sync process. Even with the memory for BTC set to 10GB, to speed things up, it’s slow. I am 28hrs far now and still at just 91%. :-1:

I run BTC Core btw.

29

What version, and edition of Bitcoin are you running? If you are not on the latest, try upgrading to the latest, that may help.

Also, take a look at the configuration settings. By default the latest bitcoin packages increase dbcache and dbbatchsize during IBD, but depending on your current version and upgrade path your settings may be set for just normal operation.

I’m running a similar N150 with 16GB memory and a 4 TB nvme SSD and it took a bit over 2 days IIRC to complete bitcoin and fulcrum syncing.

30

I am running Core 31.0:11. In the meantime it’s synced and Fulcrum is building the index. It’s on 72% now. I only noticed that core is slower on Start9 than Umbrel. Especially in the end. As long as it keeps up now, it’s ok. :slight_smile: