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

Overview of Using ESXi with a SAN 2Using ESXi with a SAN improves flexibility, efficiency, and reliability. Using ESXi with a SAN also supportscentralized management, failover, and load balancing technologies.The following are benefits of using ESXi with a SAN:• You can store data securely and configure multiple paths to your storage, eliminating a single point offailure.• Using a SAN with ESXi systems extends failure resistance to the server. When you use SAN storage, allapplications can instantly be restarted on another host after the failure of the original host.• You can perform live migration of virtual machines using VMware vMotion.• Use VMware High Availability (HA) in conjunction with a SAN to restart virtual machines in their lastknown state on a different server if their host fails.• Use VMware Fault Tolerance (FT) to replicate protected virtual machines on two different hosts. Virtualmachines continue to function without interruption on the secondary host if the primary one fails.• Use VMware Distributed Resource Scheduler (DRS) to migrate virtual machines from one host toanother for load balancing. Because storage is on a shared SAN array, applications continue runningseamlessly.• If you use VMware DRS clusters, put an ESXi host into maintenance mode to have the system migrateall running virtual machines to other ESXi hosts. You can then perform upgrades or other maintenanceoperations on the original host.The portability and encapsulation of VMware virtual machines complements the shared nature of thisstorage. When virtual machines are located on SAN-based storage, you can quickly shut down a virtualmachine on one server and power it up on another server, or suspend it on one server and resume operationon another server on the same network. This ability allows you to migrate computing resources whilemaintaining consistent shared access.This chapter includes the following topics:• “ESXi and SAN Use Cases,” on page 28• “Specifics of Using SAN Storage with ESXi,” on page 28• “ESXi Hosts and Multiple Storage Arrays,” on page 29• “Making LUN Decisions,” on page 29• “Choosing Virtual Machine Locations,” on page 30• “Layered Applications,” on page 31• “Third-Party Management Applications,” on page 32VMware, Inc. 27