This is in response to community feedback that our existing reputation
calculation is too likely to disqualify storage nodes unfairly with
extreme swings up and down.
For details and analysis, please see the data_loss_vs_dq_chance_sim.py
tool, the "tuning reputation further.ipynb" Jupyter notebook in the
storj/datascience repository, and the discussion at
https://forum.storj.io/t/tuning-audit-scoring/14084
In brief: changing the lambda and initial-alpha parameters in this way
causes the swings in reputation to be smaller and less likely to put a
node past the disqualification threshold unfairly.
Note: this change will cause a one-time reset of all (non-disqualified)
node reputations, because the new initial alpha value of 1000 is
dramatically different, and the disqualification threshold is going to
be much higher.
Change-Id: Id6dc4ba8fde1be3db4255b72282207bab5491ca3
The ApplyUpdates() method on the reputation.DB interface acts like the
similar Update() method, but can allow for applying the changes from
multiple audit events, instead of only one.
This will be necessary for the reputation write cache, which will batch
up changes to each node's reputation in order to flush them
periodically.
Refs: https://github.com/storj/storj/issues/4601
Change-Id: I44cc47767ea2d9423166bb8fed080c8a11182041
Set disqualification reason when reputations stats are updated on DB.Update.
Added tests for DisqualifyNode and for disqualification cases which happens during Update.
Change-Id: I00130ab5d9722422805159ad2f183c205de60f7e
inconsistency
The original design had a flaw which can potentially cause discrepancy
for nodes reputation status between reputations table and nodes table.
In the event of a failure(network issue, db failure, satellite failure, etc.)
happens between update to reputations table and update to nodes table, data
can be out of sync.
This PR tries to fix above issue by passing through node's reputation from
the beginning of an audit/repair(this data is from nodes table) to the next
update in reputation service. If the updated reputation status from the service
is different from the existing node status, the service will try to update nodes
table. In the case of a failure, the service will be able to try update nodes
table again since it can see the discrepancy of the data. This will allow
both tables to be in-sync eventually.
Change-Id: Ic22130b4503a594b7177237b18f7e68305c2f122
