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# FSVolume.KernelCacheCoherencyType

A type that defines how the kernel caches data.

```
enum KernelCacheCoherencyType
```

## Topics

### Coherency types

This list presents the coherency types in order of permissiveness, from least permissive to most.

[`case noCache`](/documentation/FSKit/FSVolume/KernelCacheCoherencyType/noCache)

A type that indicates all I/O goes directly to storage, without caching.

[`case readCache`](/documentation/FSKit/FSVolume/KernelCacheCoherencyType/readCache)

A type that indicates that writes bypass the cache and go directly to storage.

[`case writeBack`](/documentation/FSKit/FSVolume/KernelCacheCoherencyType/writeBack)

A type that indicates writes immediately update the cache only, followed by a deferred write to storage.

[`case writeThrough`](/documentation/FSKit/FSVolume/KernelCacheCoherencyType/writeThrough)

A type that indicates writes update cache and storage synchronously.

### Initializers

[`init?(rawValue: Int)`](/documentation/FSKit/FSVolume/KernelCacheCoherencyType/init(rawValue:))

## Relationships

### Conforms To

[`Equatable`](/documentation/Swift/Equatable)

[`Hashable`](/documentation/Swift/Hashable)

[`Sendable`](/documentation/Swift/Sendable)

[`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

---

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