Syncing a Parity Archive Node: How-To

For my experiments, I set on having an Ethereum archive node (with the full history of all the states), with Parity.

The whole process was frustrating so I’m sharing what I would have wanted to know when I started. Also see the last part if you want to try a shortcut to avoid going through the whole process.

My setup

I did the sync on a good laptop, with a huge SSD:

  • i7-2720QM CPU @ 2.20GHz
  • 16 GB of RAM
  • Samsung SSD 860 EVO 4 TB

Here, we are syncing from scratch so we have to replay the full history. An SSD is mandatory. And given the final size (that I didn’t really know beforehand), 4 TB is clearly recommended.

The sync was made with Parity 2.3 (nightly), with the following relevant options:

  • --pruning archive
  • --tracing on
  • --fat-db on
  • --cache-size 4096

The filesystem used was btrfs (because snapshots, see below).

How it went

Fun fact: Parity stalled after a few days (due to a bug), and I had to upgrade its version to nightly, were the bug was apparently fixed.

Facts:
  • It took approximately a month to sync to block 6,700,000 (the block height at that time).
  • At block 6,700,000 the disk usage for my archive node is 1.8 TiB.
  • Total written to my SSD: 74 TiB (computed from the Total_LBAs_Written SMART counter).

I highly recommend that you look at the guaranteed TBW (terabytes written) for your SSD: my 860 EVO is guaranteed for 2400 TBW which means that I consumed 3% of its guaranteed life (not too bad). But if I had a 850 EVO (guaranteed for 300 TBW) I would be at 25% of its guaranteed life!

You can see the block heigh with respect to time, in the following diagram:

graph representing block height with respect to time since sync start

The DoS attack (around block 2,700,000) didn’t take so long to process (only a day or so).

Unsurprisingly, most of the time is spent processing from the time where the network reached its capacity and the blocks were full.

Sharing a snapshot?

I would have liked to download a snapshot with all the data from someone, even if it would take a week or two: it would have been faster, and I would have avoided consuming a quarter of the life of my expensive SSD.

Also, I find it a waste to have to buy a huge SSD to do the sync if you don’t plan to stay up-to-date with the network: you could download a snapshot and do your analysis on historical data without ever needing to sync anything.

I have a snapshot of my Parity folder at block 6,700,000 and I can manage to share it, if anybody is interested.

Beware: it’s huge, and sending me an hard disk may be the best way to share it. But I’m happy to try uploading it as well.

If you have any question on this article, please contact me: ethereum at palkeo dot com.