Struct TestBlockDeviceConfig

Source

pub struct TestBlockDeviceConfig {
    pub dev_id: i32,
    pub size: u64,
    pub seed: u64,
    pub fill_percent: u32,
    pub duplicate_percent: u32,
    pub random_percent: u32,
    pub segments: usize,
    pub unprivileged: bool,
}

Expand description

Configuration for creating a test block device.

This struct contains all the parameters needed to create a procedurally generated test block device with specific characteristics for testing storage systems, compression, deduplication, and other block-level operations.

§Examples

use test_bd::TestBlockDeviceConfig;

let config = TestBlockDeviceConfig {
    dev_id: -1,  // Auto-assign device ID
    size: 1024 * 1024 * 1024,  // 1 GiB
    seed: 42,
    fill_percent: 40,
    duplicate_percent: 30,
    random_percent: 30,
    segments: 100,
    unprivileged: false,
};

// Validate the configuration
config.validate().expect("Invalid configuration");

Fields§

§dev_id: i32

Device ID for the block device.

Use -1 to automatically assign the next available device ID, or specify a non-negative value to request a specific device ID.

§size: u64

Total size of the block device in bytes.

Must be a multiple of 8 bytes and not exceed i64::MAX.

§seed: u64

Seed for the pseudo-random number generator.

Using the same seed with the same configuration will produce identical data patterns, enabling reproducible tests.

§fill_percent: u32

Percentage of the device to fill with zeros (0-100).

Fill segments are useful for testing compression.

§duplicate_percent: u32

Percentage of the device to fill with duplicate patterns (0-100).

Duplicate segments contain repeating 512-byte blocks, useful for testing deduplication.

§random_percent: u32

Percentage of the device to fill with pseudo-random data (0-100).

Random segments simulate encrypted or already-compressed data.

§segments: usize

Number of segments to divide the device into.

Must be less than size / 512. More segments create more varied data distributions but may impact performance.

§unprivileged: bool

Whether to create an unprivileged device (non-root access).

When true, the device can be accessed by non-root users (requires kernel support).

Implementations§

Source §

impl TestBlockDeviceConfig

Source

pub fn generate_segments(&self) -> Vec<SegmentInfo>

Generates the segment layout for this configuration without creating a device.

This is useful for inspecting what the device layout would be before actually creating the device, or for verification purposes.

§Examples

use test_bd::TestBlockDeviceConfig;

let config = TestBlockDeviceConfig {
    dev_id: -1,
    size: 10240,
    seed: 42,
    fill_percent: 50,
    duplicate_percent: 25,
    random_percent: 25,
    segments: 10,
    unprivileged: false,
};

let segments = config.generate_segments();
assert_eq!(segments.len(), 10);

Source

pub fn validate(&self) -> Result<(), String>

Validates the configuration parameters.

Ensures that:

Percentages sum to exactly 100
Size doesn’t exceed i64::MAX
Number of segments is reasonable for the device size

§Returns

Ok(()) if the configuration is valid
Err(String) with a descriptive error message if validation fails

§Examples

use test_bd::TestBlockDeviceConfig;

let config = TestBlockDeviceConfig {
    dev_id: -1,
    size: 10240,
    seed: 42,
    fill_percent: 50,
    duplicate_percent: 30,
    random_percent: 20,
    segments: 10,
    unprivileged: false,
};

assert!(config.validate().is_ok());