VMware VMFS

Deliver High-performance Storage for Virtual Machines

Simplify virtual machine provisioning and administration with a high performance cluster file system optimized for virtual machines. VMware VMFS, technology unique to VMware, is the default storage system for virtual machine files on physical SCSI disks and partitions. Central storage of virtual machines with VMware VMFS provides more control, flexibility and performance in managing your virtualized IT environment.

Enable Unique Capabilities that Assure Service Levels to Applications:

While conventional file systems allow only one server to have read-write access to the same file at a given time, VMFS is a cluster file system that leverages shared storage to allow multiple instances of ESX Server to read and write to the same storage, concurrently. VMFS allow you to:

Greatly simplify virtual machine provisioning and administration by efficiently storing the entire virtual machine state in a central location.
Support unique virtualization-based capabilities such as live migration of running virtual machines from one physical server to another, automatic restart of a failed virtual machine on a separate physical server, and clustering virtual machines across different physical servers.

Seamlessly Manage Virtual Machine Storage:

Get virtual disk performance close to native SCSI for even the most data-intensive applications with dynamic control of virtual storage volumes.

Enable multiple installations of ESX Server to read and write from the same storage location concurrently.
Add or delete an ESX Server from a VMware VMFS volume without disrupting other ESX Server hosts.
Create new virtual machines without relying on a storage administrator. Adaptive block sizing and addressing for growing files allows you to increase a VMFS volume on the fly.
Simplify storage management with automatic discovery and mapping of LUNs to a VMware VMFS volume.
Optimize your virtual machine I/O with adjustable volume, disk, file and block sizes.
Recover virtual machines faster and more reliably in the event of server failure with Distributed journaling.

VMware VMFS cluster file system is included in VMware Infrastructure Enterprise and Standard Editions and is available for local storage only with the Starter edition. Learn more about the VMware Infrastructure editions.

VMware VMFS Features:

Architecture:

Cluster file system. Enable virtualization-based distributed infrastructure services by storing virtual machine files on shared storage as Fibre Channel and iSCSI SAN.

Shared data file system. Enable multiple installations of ESX Server to read and write from the same storage location concurrently.

Online insertion or deletion of nodes. Add or delete an ESX Server from a VMFS volume without pausing or halting the processing of other instances of ESX Server.

On-disk disk file locking. Ensure that the same virtual machine is not powered on by multiple servers at the same time.

Performance and Scalability:

Optimized for virtual machine I/O. Store and access the entire virtual machine state efficiently from a centralized location with virtual disk performance close to native SCSI.
Adaptive block sizing. Uses large block sizes favored by virtual disk I/O. Use sub-block allocator for small files and directories.
Dynamic increase of VMFS volume size. Create new virtual machines without relying on a storage administrator. Adaptive block sizing and addressing for growing files allows to increase a VMFS volume on the fly.
Increased number of ESX Server per VMFS volume. Connect up to 32 ESX Servers to a single VMFS volume.
Extended block size and file limits. Run even the most data intensive production applications such as databases, ERP and CRM in virtual machines.
- Maximum volume size: 64 TB
- Maximum virtual disk size: 2 TB
- Maximum file size: 2 TB max
- Block size: 1MB to 8MB
Caching. Benefits from enhanced VMFS performance with volume, device, object and buffer caching.

Interoperability:

Certification. Use VMFS with a wide range of Fibre Channel and iSCSI SAN equipment. VMFS is optimized, rigorously tested and certified for these storage systems.
Idealized SCSI compliant virtual disks. Use virtual disk files that appear to the virtual machine as a mounted SCSI device. Virtual disks hide all intermittent SAN errors from the operating system, allowing even operating systems not certified for SAN to run inside a virtual machine.

Management:

LUN discovery and management. Simplify storage management with automatic discovery of LUNs in the shared storage and mapping of those LUNs to a VMFS volume.
File directories. Enable easy virtual machine administration with file directories. All files for a virtual machine are stored in a separate directory.
Direct pass through of virtual machine data. Ensure correct application behavior and data integrity for applications running in virtual machines. VMware VMFS preserves the internal file system semantics of the operating system running inside the virtual machine.
Unified hierarchical namespace. Manage all available physical disks, logical volumes and VMware VMFS volumes with a consistent namespace that eliminates potential conflicts.

High Availability:

Virtual machine snapshots. Increase application availability while reducing backup windows using virtual machine snapshots. Create a point-in-time copy of virtual machine data that can be used for testing, backup, and recovery operations.
Hot add virtual disk. Add virtual disk to a running virtual machine to increase available resources or for backup.
Distributed journaling. Recover virtual machines faster and more reliably in the event of server failure.

VMware Documentation
	Download the VMware VMFS Product Brochure (PDF).