How to Chill
Staking bonds can be in any of the three states: validating, nominating, or chilled (neither validating nor nominating). When a staker wants to temporarily pause their active engagement in staking but does not want to unbond their funds, they can choose to "chill" their involvement and keep their funds bonded.
An account can step back from participating in active staking by clicking "Stop" under the Network >
Staking > Account actions page in PolkadotJS Apps or by calling the
chill extrinsic in the
staking pallet.
When an account chooses to chill, it becomes inactive in the next era. The call must be signed by
the controller account, not the stash.
If you need a refresher on the different responsibilities of the stash and controller account when staking, take a look at the accounts section in the general staking guide.
Consideration for Staking Election
A bond that is actively participating in staking but chilled would continue to participate in staking for the rest of the current era. If the bond was chilled in sessions 1 through 4 and continues to be chilled for the rest of the era, it would NOT be selected for election in the next era. If a bond was chilled for the entire session 5, it would not be considered in the next election. If the bond was chilled in session 6, its participation in the next era's election would depend on its state in session 5.
Chilling as a Nominator
When you chill after being a nominator, your nominations will be reset. This means that when you decide to start nominating again you will need to select validators to nominate once again. These can be the same validators if you prefer, or, a completely new set. Just be aware - your nominations will not persist across chills.
Your nominator will remain bonded when it is chilled. When you are ready to nominate again, you will not need to go through the whole process of bonding again, rather, you will issue a new nominate call that specifies the new validators to nominate.
Chilling as a Validator
When you voluntarily chill after being a validator, your nominators will remain. As long as your nominators make no action, you will still have the nominations when you choose to become an active validator once again. You bond however would not be listed as a nominable validator thus any nominators issuing new or revisions to existing nominations would not be able to select your bond.
When you become an active validator, you will also need to reset your validator preferences (commission, etc.). These can be configured as the same values set previously or something different.
Involuntary Chills
If a validator was unresponsive for an entire session, the validator bond would be chilled in a process known as involuntary chilling. When a validator has been involuntarily chilled, it may restrict the validator from being selected in the next election depending on the session in which it was chilled (see considerations above). A chilled validator may re-declare the intent to validate at any time. However, it is recommended that the validator attempts to determine the source of the chill before doing so.
Slashing may also result in an involuntary chill. However, in that scenario, the validator would also lose their nominations. By this action, even if the validator re-declares its intent to validate before session 5, there wouldn't be sufficient nominations to re-elect the node into the active set.
Nominators have the option to renominate a slashed validator using a display row in Polkadot-JS UI. This row is displayed in the "Account Actions" tab for the nominator under a heading that says "Renomination required".
Chill Other
An unbounded and unlimited number of nominators and validators in Polkadot's NPoS is not possible
due to constraints in the runtime. As a result, multiple checks are incorporated to keep the size of
staking system manageable, like mandating minimum active bond requirements for both nominators and
validators. When these requirements are modified through on-chain governance, they can be enforced
only on the accounts that newly call nominate or validate after the update. The changes to the
bonding parameters would not automatically chill the active accounts on-chain which do not meet the
requirements.
ChillThreshold defines how close to the max nominators or validators we must reach before users
can start chilling one-another. This value is currently set to
%
For instance, let us consider a scenario where the minimum staking requirement for nominators is
changed from 80 DOTs to 120 DOTs. An account that was actively nominating with 80 DOTs before this
update would still keep receiving staking rewards. To handle this corner case, the chillOther
extrinsic was incorporated which also helps to keep things backwards compatible and safe. The
chillOther extrinsic is permissionless and any third party user can target it on an account where
the minimum active bond is not satisfied, and chill that account. The list of addresses of all the
active validators and their nominators can be viewed by running
validator stats script.
Through Referendum 90, maxNominatorCount on
Polkadot is set to None eliminating the upper bound on the number of nominators on the network.
Due to this, the chillOther extrinsic on Polkadot network has no effect as the chill threshold
will never be met.