Enum IoEngine

pub enum IoEngine {
    Sync,
    Async,
}

Block device IO engine, default to “Sync”. The Async engine leverages io_uring for executing requests in an async manner, therefore getting overall higher throughput by taking better advantage of the block device hardware, which typically supports queue depths greater than 1. The block IO engine is configured via the PUT /drives API call (pre-boot only), with the io_engine field taking two possible values:

• Sync (default)
• Async (in developer preview) The Sync variant is the default, in order to provide backwards compatibility with older Firecracker versions. Note vhost-user block device is another option for block IO that requires an external backend process.

Variants

Sync

Async

Firecracker requires a minimum host kernel version of 5.10.51 for the Async IO engine. This requirement is based on the availability of the io_uring subsystem, as well as a couple of features and bugfixes that were added in newer kernel versions. If a block device is configured with the Async io_engine on a host kernel older than 5.10.51, the API call will return a 400 Bad Request, with a suggestive error message.

Trait Implementations

impl Clone for IoEngine

fn clone(&self) -> IoEngine

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for IoEngine

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for IoEngine

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for IoEngine

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for IoEngine

fn cmp(&self, other: &IoEngine) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for IoEngine

fn eq(&self, other: &IoEngine) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for IoEngine

fn partial_cmp(&self, other: &IoEngine) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for IoEngine

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for IoEngine

impl Eq for IoEngine

impl StructuralPartialEq for IoEngine