Virtual Flash File System in ESXi 5.5

Products

• VMware vSphere ESXi

Issue/Introduction

This article provides information on Virtual Flash File System (VFFS) in ESXi 5.5. VFFS is the file system used by VMware Virtual Flash.

For more information on configuring and setting up Virtual Flash see the About VMware vSphere Flash Read Cache section in vSphere Storage Guide.

Environment

VMware vSphere ESXi 5.5

Resolution

VFFS is a derivative of VMFS, which is optimized for SSDs and is used to group the physical SSDs into a single caching resource pool. It is a non-persistent resource and, therefore, virtual machines cannot be stored in it.

A VFFS resource pool can be created from mixed resources. All devices types are treated the same and no distinction is made between SAS, SATA, PCI express connectivity.

Note: You must consider any other differences in read/write speeds when creating a VFFS from mixed SSDs and group similar performing devices together to maximize performance.