lotus daemon first-use could default to reading a snapshot archive

[snadrus]

Checklist

• This is not brainstorming ideas. If you have an idea you'd like to discuss, please open a new discussion on the lotus forum and select the category as Ideas.
• I have a specific, actionable, and well motivated feature request to propose.

Lotus component

• lotus daemon - chain sync
• lotus fvm/fevm - Lotus FVM and FEVM interactions
• lotus miner/worker - sealing
• lotus miner - proving(WindowPoSt/WinningPoSt)
• lotus JSON-RPC API
• lotus message management (mpool)
• Other

What is the motivation behind this feature request? Is your feature request related to a problem? Please describe.

1. I want simpler, faster day-one behavior.
2. I see no need in keeping snapshots & diffs on Forest when a simple tooling update will make those huge downloads obsolete.

Describe the solution you'd like

lotus daemon --get-snapshot
should:

1. Consult the forest archive: https://forest-archive.chainsafe.dev/list/calibnet/latest-v2
   (which actually isn't in the docs)
   to find the files for all the diffs & pieces.

2. Stream the snapshot diffs into the node, which is faster than downloading them first.

Precedent:
Params are automatically downloaded already.

Describe alternatives you've considered

The manual way is to:

1. read the docs
2. go searching for an archive using the right keywords (it took this long-time developer a few tries)
3. do the download, wait
4. do the import with a flag
5. then start it without flags

Additional context

Curio implemented many changes to make it easy for developers & SPs to get moving faster. Automating away hurdles will get more people exploring what the platform has to offer.

[rvagg]

@LesnyRumcajs could we get a JSON or just text version of https://forest-archive.chainsafe.dev/list/calibnet/latest-v2 and https://forest-archive.chainsafe.dev/list/mainnet/latest-v2 that we could query and not have to parse HTML? Maybe latest-v2.json. I'm not sure how many should be included though. Perhaps the .json is just the latest one cause that's all we'd probably need when doing this programmatically I think.

[LesnyRumcajs]

@rvagg I'll forward this to the infrastructure team who are managing the snapshots and let you know.

[LesnyRumcajs]

That is, unless you just want to grab the latest snapshot like Forest does with the --auto-download-snapshot flag.

[rvagg]

Yeah, that would work too, is that a v2 snapshot though @LesnyRumcajs ?

[LesnyRumcajs]

Yes, v2 snapshots are the default (the listing URL might be confusing, but hopefully it'll get rectified)

❯ forest-tool archive metadata forest_snapshot_calibnet_2025-11-03_height_3161280.forest.car.zst
Snapshot version:           2
Head Tipset:                bafy2bzacedhes7xhg47ahwl7x4ll6t7dp6kg5nte6zu2lkh67nsgkaizlgsbs
                            bafy2bzaceaa5lqxxqkmsie6cxgdb6arrr7lgedwy3ubr2fuwyhmrgafon3pie
F3 data:                    bafk2bzacebxidwz6k63v3ik7peab7e4nk34zeko2qi2bygeqlqu7oo7mxhamk
F3 snapshot version:        1
F3 snapshot first instance: 0
F3 snapshot last instance:  752676

https://docs.forest.chainsafe.io/filecoin_services/#latest-filecoin-snapshots

[LesnyRumcajs]

By the way @snadrus :

Consult the forest archive: https://forest-archive.chainsafe.dev/list/calibnet/latest-v2
(which actually isn't in the docs)
to find the files for all the diffs & pieces.

Is there a particular doc that should be updated? The snapshot links are available at https://docs.filecoin.io/networks/mainnet#resources and https://docs.filecoin.io/networks/calibration, in addition to Forest docs. I see mentions in the Lotus docs as well https://lotus.filecoin.io/lotus/manage/chain-management/#lightweight-snapshot.

[snadrus]

The docs were clear. I was skimming and missed it.