gitlab.com/SkynetLabs/skyd@v1.6.9/skymodules/renter/hostdb/consts.go

package hostdb

import (
	"time"

	"gitlab.com/SkynetLabs/skyd/build"
)

const (
	// historicInteractionDecay defines the decay of the HistoricSuccessfulInteractions
	// and HistoricFailedInteractions after every block for a host entry.
	historicInteractionDecay = 0.9995

	// historicInteractionDecalLimit defines the number of historic
	// interactions required before decay is applied.
	historicInteractionDecayLimit = 500

	// hostRequestTimeout indicates how long a host has to respond to a dial.
	hostRequestTimeout = 2 * time.Minute

	// hostScanDeadline indicates how long a host has to complete an entire
	// scan.
	hostScanDeadline = 4 * time.Minute

	// maxHostDowntime specifies the maximum amount of time that a host is
	// allowed to be offline while still being in the hostdb.
	maxHostDowntime       = maxHostDownTimeInDays * 24 * time.Hour
	maxHostDownTimeInDays = 20

	// maxSettingsLen indicates how long in bytes the host settings field is
	// allowed to be before being ignored as a DoS attempt.
	maxSettingsLen = 10e3

	// minScans specifies the number of scans that a host should have before the
	// scans start getting compressed.
	minScans = 12

	// minScansForSpeedup is the number of successful scan that needs to be
	// completed before the dial up timeout for scans is reduced. This ensures
	// that we have a sufficient sample size of scans for estimating the worst
	// case timeout.
	minScansForSpeedup = 25

	// recentInteractionWeightLimit caps the number of recent interactions as a
	// percentage of the historic interactions, to be certain that a large
	// amount of activity in a short period of time does not overwhelm the
	// score for a host.
	//
	// Non-stop heavy interactions for half a day can result in gaining more
	// than half the total weight at this limit.
	recentInteractionWeightLimit = 0.01

	// saveFrequency defines how frequently the hostdb will save to disk. Hostdb
	// will also save immediately prior to shutdown.
	saveFrequency = 2 * time.Minute

	// scanSpeedupMedianMultiplier is the number with which the median of the
	// initial scans is multiplied to speedup the initial scan after
	// minScansForSpeedup successful scans.
	scanSpeedupMedianMultiplier = 5

	// storageCompetitionFactor is the amount of competition we expect to have
	// over a volume of storage on a host. If a host has 1 TB of storage
	// remaining and we are actively uploading, it is unlikely that we will get
	// the full 1 TB, because other renters will also be actively uploading to
	// the host. A storageCompetitionFactor of 0.25 indicates that we will
	// likely get 0.25 TB out of the 1 TB that the host has.
	//
	// TODO: Eventually we will want to set this value dynamically based on
	// factors such as our own speed and potentially per-host characteristics.
	// Buf for now we use a global constant.
	storageCompetitionFactor = 0.25

	// storagePenaltyExponentiation is the exponent that we apply to the storage
	// penalty. If the host has half as much storage as we would like and the
	// storagePenaltyExponentiation is 2, then the final score for the host
	// would be (0.5)^2 = 0.25.
	storagePenaltyExponentitaion = 2.0

	// storageSkewMultiplier is a factor that we multiply with a host's ideal
	// storage. The ideal storage is the amount of data that would be stored on
	// the host if the renter's expected storage total (including redundancy)
	// was spread evenly across all of the hosts. The skew multiplier adjusts
	// for the fact that data will not be evenly spread across the hosts.
	//
	// A value of '1.0' indicates that storage is spread perfectly evenly. A
	// value of '2.0' means that the host with the most data stored on it will
	// have twice as much storage as it would if the data were spread perfectly
	// evenly. Values closer to 1 mean less skew, values more than 1 mean more
	// skew.
	storageSkewMultiplier = 1.75

	// txnFeesUpdateRatio is the amount of change we tolerate in the txnFees
	// before we rebuild the hosttree.
	txnFeesUpdateRatio = 0.05 // 5%
)

var (
	// hostCheckupQuantity specifies the number of hosts that get scanned every
	// time there is a regular scanning operation.
	hostCheckupQuantity = build.Select(build.Var{
		Standard: int(2500),
		Dev:      int(6),
		Testing:  int(5),
	}).(int)

	// scanningThreads is the number of threads that will be probing hosts for
	// their settings and checking for reliability.
	maxScanningThreads = build.Select(build.Var{
		Standard: int(80),
		Dev:      int(4),
		Testing:  int(3),
	}).(int)
)

var (
	// maxScanSleep is the maximum amount of time that the hostdb will sleep
	// between performing scans of the hosts.
	maxScanSleep = build.Select(build.Var{
		Standard: time.Hour * 8,
		Dev:      time.Minute * 10,
		Testing:  time.Second * 5,
	}).(time.Duration)

	// scanCheckInterval is the interval used when waiting for the scanList to
	// empty itself and for waiting on the consensus set to be synced.
	scanCheckInterval = build.Select(build.Var{
		Standard: time.Second,
		Dev:      time.Second,
		Testing:  100 * time.Millisecond,
	}).(time.Duration)

	// minScanSleep is the minimum amount of time that the hostdb will sleep
	// between performing scans of the hosts.
	minScanSleep = build.Select(build.Var{
		Standard: time.Hour + time.Minute*20,
		Dev:      time.Minute * 3,
		Testing:  time.Second * 1,
	}).(time.Duration)
)