Extremely slow Bitcoin Knots initial sync

Bitcoin and Lightning
1

I am trying to sync the blockchain with Bitcoin Knots. The first 70% went smooth, however after 70% it entered an extreme slow phase with not even 1% per day, to sometimes just 0.1%. The logs don’t show useful errors and setup should be fine:

  • raspberry pi5 with 8gb memory
  • Samung T7 2TB SSD hard drive connected through USB3
  • SanDisk 32 GB Micro SD Ultra 120 MB/s
  • Connected with an ethernet cable to fiber optic internet

Things I’ve tried:

  • increase dbcache to 4096
  • only use Clearnet for peer connections
  • restart the node/umbrel several times
  • unplug and plug the ethernet cable

With this pace it’s going to take a full year to sync, what could be the problem? Would reflashing the SD card might help? Really out of things to try.

Would be great if anyone has any suggestions

2

Not sure if you found a solution to this? I have a nearly identical setup to you (only difference being that I run Umbrel OS directly from the T7 instead of Micro SD) and ran into a similar thing. Around 70% sync it slowed to about .05% per day. I was going to just wait it out, but then calculated it would take 100+ days to complete the download.

I THINK from looking at HTOP through umbrel SSH, that the I/O Wait time was a major culprit. Was speculating with the help of GPT that the T7 hard drive was having a hard time with the high frequency of read/write. I’m not 100% sure that was the issue, but I tried countless things to speed up the verification process without any success.

I eventually decided to just download the blockchain to another SSD using my computer, then transferred the files from the second SSD to the T7 through Umbrel on the raspberry pi using SSH. (I used GPT to get the commands for the terminal)

After running into issues with the initial block download on the secondary drive on my desktop, I found my drive kept going to sleep, so threw some commands at it to prevent sleeping and started fresh since I had corruption issues. Finally the entire download completed, and I was able to successfully transfer all of the files from my second drive to the T7 running umbrel. Had to do the transfer via SSH since Umbrel OS says it can’t use the drive.

I am now running at 100% on the Umbrel app. Not exactly sure why the bottleneck but found a roundabout way to get there I guess.