Parity-ethereum: Slow archive sync

[k06a]

_Before filing a new issue, please provide the following information._

I'm running:

• Which Parity version?: 1.8.11
• Which operating system?: MacOS (Mac Book Pro 15" 2017)
• How installed?: homebrew
• Are you fully synchronized?: yes
• Which network are you connected to?: ropsten
• Did you try to restart the node?: yes

I am using following options:

• --pruning archive
• --cache-size 4096
• --mode active
• --db-compaction ssd

First 2.2M blocks were synced at speed about 60Mgas/s, but then I stopped process and then continued and speed now is about 0-1Mgas/s and sometimes it is about 40Mgas/s. The most of time speed is 0-1Mgas/s, about 90%.

I also can see a lot of hidden space on my SSD it is always growing and sometimes pruning to zero:

[k06a]

[k06a]

Didn't know what just happened:

[k06a]

For some reason it downloaded more than 2.4M blocks and I noticed --networkid 3 not gives me ropsten, added --chain ropsten and restarted with empty DB.

Is it possible to have two configs in one? For mainnet to be light and for ropsten to be archive.

[k06a]

I like current speed, not going to stop it.

[Tbaut]

@k06a the network was attacked during these blocks and it is therefore expected to have a slower sync since the blocks have a great amount of transactions. See our documentation

Network ID 3 is Ropsten but the flags --network-id and --networkid override the network id, it does not select the chain to sync (you found it, the right flag is --chain)

It is definitely possible to have 2 config files, just load the one you need using -c your-file.toml

For quicker feedback, feel free to ask anything in the gitter chat