Struct StorageConfiguration 

pub struct StorageConfiguration {

    pub iops: u64,
    pub bandwidth: u64,
    pub read_latency: LatencyDistribution,
    pub write_latency: LatencyDistribution,
    pub sync_latency: LatencyDistribution,
    pub read_fault_probability: f64,
    pub write_fault_probability: f64,
    pub crash_fault_probability: f64,
    pub misdirect_write_probability: f64,
    pub misdirect_read_probability: f64,
    pub phantom_write_probability: f64,
    pub sync_failure_probability: f64,
    pub disk_stall_probability: f64,
    pub disk_stall_duration: Duration,
    pub disk_throttle_probability: f64,
    pub disk_throttle_duration: Duration,
    pub disk_throttle_iops_multiplier: f64,
    pub disk_throttle_bandwidth_multiplier: f64,
}

Configuration for storage simulation parameters.

This struct contains all settings related to storage simulation including performance characteristics and fault injection probabilities.

Fields

iops: u64

I/O operations per second limit.

Typical values:

• NVMe SSD: 100,000-500,000 IOPS
• SATA SSD: 25,000-100,000 IOPS
• HDD: 100-200 IOPS

bandwidth: u64

Maximum bandwidth in bytes per second.

Typical values:

• NVMe SSD: 3,000-7,000 MB/s
• SATA SSD: 500-600 MB/s
• HDD: 100-200 MB/s

read_latency: LatencyDistribution

Latency distribution for read operations.

Typical values:

• NVMe SSD: 20-100µs
• SATA SSD: 50-200µs
• HDD: 2-10ms

write_latency: LatencyDistribution

Latency distribution for write operations.

Typical values:

• NVMe SSD: 20-100µs
• SATA SSD: 100-500µs
• HDD: 2-10ms

sync_latency: LatencyDistribution

Latency distribution for sync/flush operations.

Sync operations ensure data durability and typically take longer than regular read/write operations.

read_fault_probability: f64

Probability of read operation failing (0.0 - 1.0).

Real-World Scenario

Simulates disk read errors, ECC failures, or media degradation.

write_fault_probability: f64

Probability of write operation failing (0.0 - 1.0).

Real-World Scenario

Simulates write failures due to disk full, bad sectors, or media errors.

crash_fault_probability: f64

Probability of crash fault during operation (0.0 - 1.0).

Real-World Scenario

Simulates sudden power loss or system crash during I/O. Tests crash consistency and recovery logic.

misdirect_write_probability: f64

Probability of write landing at wrong location (0.0 - 1.0).

Real-World Scenario

Simulates misdirected writes where data is written to a different block than intended. Tests checksum validation and corruption detection. TigerBeetle ref: storage fault injection

misdirect_read_probability: f64

Probability of read returning data from wrong location (0.0 - 1.0).

Real-World Scenario

Simulates misdirected reads where data is read from a different block than intended. Tests checksum validation. TigerBeetle ref: storage fault injection

phantom_write_probability: f64

Probability of write appearing to succeed but not persisting (0.0 - 1.0).

Real-World Scenario

Simulates phantom writes where the write reports success but data is lost before reaching stable storage. Tests durability guarantees.

sync_failure_probability: f64

Probability of sync/flush operation failing (0.0 - 1.0).

Real-World Scenario

Simulates fsync failures which can indicate serious storage issues. Tests error handling in durability-critical code paths.

disk_stall_probability: f64

Per-operation probability of entering a stall episode (0.0 - 1.0).

During a stall the disk is frozen until the episode expires; any I/O scheduled in that window waits out the remaining time before completing.

disk_stall_duration: Duration

How long a stall episode freezes the disk once entered.

disk_throttle_probability: f64

Per-operation probability of entering a throttle episode (0.0 - 1.0).

During a throttle the effective IOPS/bandwidth are divided by the configured multipliers for the duration of the episode.

disk_throttle_duration: Duration

How long a throttle episode reduces throughput once entered.

disk_throttle_iops_multiplier: f64

Divisor applied to effective IOPS during a throttle episode (>= 1.0).

E.g. 10.0 makes the disk handle one tenth its normal IOPS.

disk_throttle_bandwidth_multiplier: f64

Divisor applied to effective bandwidth during a throttle episode (>= 1.0).

Implementations

impl StorageConfiguration

pub fn new() -> Self

Create a new storage configuration with default settings.

pub fn random_for_seed() -> Self

Create a randomized storage configuration for chaos testing.

Uses deterministic random values based on the simulation seed to create varied configurations across test runs.

pub fn swarm_for_seed() -> Self

Create a swarm-testing storage configuration for seed-based testing.

Starts from random_for_seed, then disables each fault family with ~50% probability (drawn from the independent CONFIG_RNG stream). This implements swarm testing (Groce et al., ISSTA 2012): each seed exercises a random subset of storage fault families — including the all-off subset — instead of every family being slightly on at once (which lets families crowd each other out, the passive-suppression anti-pattern).

pub fn apply_buggify_knobs(&mut self)

Spike selected disk knob magnitudes under buggify (FDB’s if (randomize && BUGGIFY) KNOB = random(lo, hi)).

Composes on top of random_for_seed / swarm_for_seed: each knob keeps its sampled value unless its own buggify_knob! call site fires for the seed. Demonstrates both throttling down (IOPS/bandwidth → extreme-slow disk) and spiking a fault rate up. A representative subset — extend by adding more buggify_knob! lines.

pub fn fast_local() -> Self

Create a configuration optimized for fast local testing.

Minimal latencies and no fault injection for predictable, fast test execution.

Trait Implementations

impl Clone for StorageConfiguration

fn clone(&self) -> StorageConfiguration

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for StorageConfiguration

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for StorageConfiguration

fn default() -> Self

Returns the “default value” for a type.