Host gouging tolerance / reduce migrations

[jdannenberg]

Description

TLDR; On my renterd instance most migrations take place because some pricing values increased a tiny bit over my set limits. This may happen due to fiat currency conversions happening at random times and some hosts update before my renter updates, etc.. This massively increases costs (egress to download slabs, ingress again to upload them, contract fees).

Relevant discord discussion (https://discord.com/channels/809849352516141067/946328563320238190/1421082563434250312):

jjjjulian4247 — Yesterday at 12:34 PM
How to avoid too many migrations due to price gouging? What I think I need is different values for "acceptable prices for forming new contracts" and "maximum amount of surcharge before starting migration".

So I accept 1.6$ / TB storage price but migrations only happen if host increases to 2$/TB. Is that sensible? 

What I did just now (and I am not sure that works) was to set acceptable storage price to 1,65$, same with ingress and egress so using that second decimal place.

Reasoning behind that is that I assume (as I do) that hosters set dollarprices and then there are fluctuations and my renter is not adapting pricing accordingly or there is some small discrepancy and boom. 17000 migrations.
Nick — Yesterday at 1:36 PM
that's a very valid request. if renter sets price to $2 and hostd sets price to $2  which might translate to 400 SC if the price drops a bit but the hostd updates before the renterd updates then it'll be 406 for the hostd and 400 for renterd ->price gouging
or maybe set a % of allowed price increase
or even better. calculate the loss of a price increase over one year and the loss of migration and choose what's cheeper
if price is over by 6 coins that's 72 coins per year loss per TB. you would spend 400 SC for the new contract + 400 or more for download and 50-60 for upload 
@jjjjulian4247 as a start you might set limits wtih $0.01 to 0.02 above the round value - like $2.02. a lot of hosts set price 1.98 for that same reason, but that doesn't solve the problem completely

Version

v2.7.0-beta.1

What operating system are you running (e.g. Ubuntu 22.04, macOS, Windows 11)?

official container

Anything else?

No response

[jdannenberg]

@chris124567 @peterjan @ChrisSchinnerl I created this issue to get opinions from you on how to best realize it, respectively how you envision it to be implemented.

I am planning on implementing at least some basic functionality in that regard if I get the time.

The most sophisticated approach would be (citing Nick)

or even better. calculate the loss of a price increase over one year and the loss of migration and choose what's cheeper
if price is over by 6 coins that's 72 coins per year loss per TB. you would spend 400 SC for the new contract + 400 or more for download and 50-60 for upload

A much simpler approach would be to ignore host gouging up to a certain percentage for existing active good contracts. Or even ask for manual confirmation if migration is only triggered because of gouging and not because of offline host.

[ChrisSchinnerl]

I would be open to implementing a gouging leeway that we apply when:

• forming contracts to avoid forming contracts with hosts too close to the gouging cutoff
• when moving bad contracts into the set again to make sure they satisfy the setting

It could be a constant 80% of the gouging settings to keep the initial implementation simple. If, after some testing, there is any desire to make this configurable we can revisit.