vsphere-esxi-vcenter-server-55-storage-guide

vSphere Storage• Virtual SAN takes up entire disks, including SSD and data disks, and does not share disks with otherfeatures.• You can have multiple Virtual SAN clusters for each vCenter Server instance.Characteristics of a Virtual SAN Datastore• Virtual SAN creates a single Virtual SAN datastore accessible to all hosts in the cluster, whether or notthey have disks. All hosts can also mount any other datastores, VMFS or NFS.• If you have multiple Virtual SAN clusters for each vCenter Server, each cluster provides a Virtual SANdatastore. You can use Storage vMotion to move virtual machines between the Virtual SAN datastores.• Only HDD disks contribute to the capacity of the datastore. The capacity of SSDs is not counted as partof the datastore.• In automatic mode, a Virtual SAN datastore dynamically grows when you add hosts to a Virtual SANcluster, or disks to any cluster member.About Virtual SAN DatastoresAfter you enable Virtual SAN on a cluster, a single Virtual SAN datastore is created. It appears as anothertype of datastore on the list of datastores in addition to VMFS and NFS.A Virtual SAN datastore uses multiple storage components, or disk groups, distributed across the ESXihosts in the cluster.A single Virtual SAN datastore provides different Quality of Service (QoS) levels for each virtual machine oreach virtual disk.In the vCenter Server, storage characteristics of the Virtual SAN datastore appear as a set of capabilities. Youcan reference these capabilities when creating a storage policy for virtual machines. When you later deployvirtual machines, Virtual SAN uses this policy to place virtual machines in the optimal manner based on thevirtual machine requirements.See Chapter 20, “About Virtual Machine Storage Policies,” on page 195.Requirements for Virtual SANBefore you activate Virtual SAN, verify that your environment meets all requirements.Your environment must meet specific host and storage requirements. For networking requirements, see“Virtual SAN Networking Requirements and Best Practices,” on page 177.Host RequirementsA minimum of three hosts contributing local disks, at least one SSD and one HDD, are required.Install ESXi 5.5 on each host. You can add the hosts to the Virtual SAN cluster during initial setup of thecluster, or you can add hosts later.The hosts must be managed by vCenter Server 5.5. Not all hosts need to have local storage. ESXi memoryrequirements: at least 4GB of RAM on each host.Storage RequirementsVirtual SAN supports a limited number of storage devices, which are listed on the vSphere CompatibilityGuide. Your environment must meet the following requirements.• At least one SAS or SATA Solid State Drive (SSD). Make sure that Flash Read Cache does not use SSDs.Do not format SSDs with VMFS or any other file system.176 VMware, Inc.