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

vSphere Storage• “SAN Storage Backup Considerations,” on page 32ESXi and SAN Use CasesWhen used with a SAN, ESXi can benefit from multiple vSphere features, including Storage vMotion,Distributed Resource Scheduler (DRS), High Availability, and so on.Using ESXi in conjunction with a SAN is effective for the following tasks:Storage consolidationand simplification ofstorage layoutMaintenance with zerodowntimeLoad balancingDisaster recoverySimplified arraymigrations and storageupgradesIf you are working with multiple hosts, and each host is running multiplevirtual machines, the storage on the hosts is no longer sufficient and externalstorage is required. Choose a SAN for external storage to provide a simplersystem architecture along with other benefits.When performing ESXi host or infrastructure maintenance, use vMotion tomigrate virtual machines to other host. If shared storage is on the SAN, youcan perform maintenance without interruptions to the users of the virtualmachines. Virtual machine working processes continue throughout amigration.You can add a host to a DRS cluster, and the host's resources become part ofthe cluster's resources. The distribution and usage of CPU and memoryresources for all hosts and virtual machines in the cluster are continuouslymonitored. DRS compares these metrics to an ideal resource utilization. Idealutilization takes into account the attributes of the cluster's resource pools andvirtual machines, the current demand, and the imbalance target. It thenperforms (or recommends) virtual machine migrations accordingly.You can use VMware High Availability to configure multiple ESXi hosts as acluster to provide rapid recovery from outages and cost-effective highavailability for applications running in virtual machines.When you purchase new storage systems or arrays, use Storage vMotion toperform live automated migration of virtual machine disk files from existingstorage to their new destination without interruptions to the users of thevirtual machines.Specifics of Using SAN Storage with ESXiUsing a SAN in conjunction with an ESXi host differs from traditional SAN usage in a variety of ways.When you use SAN storage with ESXi, keep in mind the following considerations:• You cannot use SAN administration tools to directly access operating systems of virtual machines thatuse the storage. With traditional tools, you can monitor only the VMware ESXi operating system. Youuse the vSphere Web Client to monitor virtual machines.• The HBA visible to the SAN administration tools is part of the ESXi system, not part of the virtualmachine.• Typically, your ESXi system performs multipathing for you.28 VMware, Inc.