Access to shared storage in a VMware vSphere environment is made possible by VMware vStorage VMFS, high-performance cluster file system designed specifically for virtual machines.
Designed, constructed and optimized for the virtual server environment, VMware vStorage VMFS increases resource utilization by providing multiple virtual machines with shared access to a consolidated pool of clustered storage. VMware vStorage VMFS also provides the foundation for distributed infrastructure services such as live migration of virtual machines and virtual disk files, as well as distributed resource scheduling, consolidated backup and automated disaster recovery.
As a file system, VMware vStorage VMFS stores all the files that make up the virtual machine in a single directory. Optimized to support large files and also performing many small concurrent writes. With automated handling virtual machine files, VMware vStorage VMFS provides encapsulation of the entire virtual machine so that it can easily become part of a disaster recovery solution. In fact, VMware vStorage VMFS is one of the key reasons why VMware Infrastructure 3 was named TechTarget’s 2006 Disaster Recovery Product of the Year.
As a logical volume manager, VMware vStorage VMFS enables an interface to storage resources so that several types of storage (SAN, iSCSI and NAS) can be presented as datastores on which virtual machines can reside. Enabling dynamic growth of those datastores through aggregation of storage resources, VMware vStorage VMFS provides the ability to increase a shared storage resource pool with minimal or no downtime.
VMware vStorage VMFS vs. Conventional File Systems
Conventional file systems allow only one server to have read-write access to the same file at a given time. By contrast, VMware vStorage VMFS uses shared storage to allow multiple instances of VMware ESX concurrent read and write access to the same storage resources.
VMware vStorage VMFS utilizes distributed journaling to allow fast and resilient recovery across these multi-server resource pools. Moreover, VMware vStorage VMFS provides the virtual machine snapshot capabilities so necessary for disaster recovery, and is the interface that VMware Consolidated Backup (VCB) uses to provide proxy backup of virtual environments.
VMware vStorage VMFS vs. CFS and CVM
VMware vStorage VMFS does not have every feature found today in other cluster file system (CFM) and cluster volume management (CVM) systems. However, there is no other CFS/CVM that provides the capabilities of VMware vStorage VMFS. Its distributed locking methods forge the link between the virtual machine and the underlying storage resources in a manner that no other CFS or CVM can equal. The unique capabilities of VMware vStorage VMFS allow virtual machines to join a cluster seamlessly, with no management overhead.
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Learn about your storage connectivity options when using Fibre Channel or find resources and best practices for deploying shared storage for virtual machines.
