# Enum - HostMemoryTierFlags(vim.host.MemoryTierFlags)

Since
  vSphere API 7.0.3.0

## Enum Description

Enumeration of flags pertaining to a memory tier.

Here are some examples of what the flags will look like for various memory configurations:

- Traditional memory (MemoryTieringType#noTiering): The host has a DRAM tier for the main memory and nothing else. The DRAM tier will have the MemoryTierFlags#memoryTier flag.
- App Direct mode (MemoryTieringType#noTiering): The host has a DRAM tier and a PMem tier, but the two are independent and unrelated. The PMem tier is non-volatile and is exposed as an NVDIMM device. Applications can decide whether to direct the reads and writes to DRAM or PMem by using the appropriate system call. The DRAM tier will have the MemoryTierFlags#memoryTier flag and the PMem tier will have the MemoryTierFlags#persistentTier flag.
- Memory mode (MemoryTieringType#hardwareTiering): The host has a DRAM tier and a PMem tier, but the DRAM is hidden from applications and is just a cache for the PMem main memory. The PMem tier is volatile, and is abstracted by the hardware layer to look like traditional memory. Applications can read from/write to memory using the traditional memory system calls. The memory controller in the hardware will internally direct those to the DRAM cache first, and on a cache miss redirect them to the PMem main memory. The DRAM tier will have the MemoryTierFlags#cachingTier flag and the PMem tier will have the MemoryTierFlags#memoryTier flag.

Enum Constants

Name | Description
--- | ---
cachingTier | Flag indicating that the tier is a cache for main memory.
memoryTier | Flag indicating that the tier is the primary memory tier visible from the host.
persistentTier | Flag indicating that the tier is used as non-volatile storage, e.g. PMem in App Direct mode.

Show WSDL type definition
<simpleType xmlns="http://www.w3.org/2001/XMLSchema" xmlns:vsan="urn:vsan" name="HostMemoryTierFlags"> <restriction base="xsd:string"> <enumeration value="memoryTier"/> <enumeration value="persistentTier"/> <enumeration value="cachingTier"/> </restriction> </simpleType>