Dell EqualLogic PS6210XS EqualLogic Group Manager Administrator s Guide PS Ser - Page 154

Running Defrag Tools Run defragmentation tools (such as fstrim, windows manual defrag, or esxtool) during periods of low I/O activity, because these operations might result in large numbers of unmapping operations and reduce array performance. XCopy Support for VVol Datastores SCSI Extended Copy (XCopy) now supports VVol-based datastores. This feature is typically used in live migration of VMs by the ESX server. XCopy enables the storage arrays to make full copies of data within the array without having the host read and write the data. This operation reduces the time and network load when cloning virtual machines, provisioning from a template, or migrating with vMotion. NOTE: The following requirements apply to XCopy for VVol datastores: • ESXi issues the XCopy only when the VM is powered on. • To use XCopy, the members must be part of the same group. • The datamover supports VAAI offload using XCopy for migrations from VMFS to VVols but does not support migrations from VVols to VMFS. The XCopy feature is enabled by default when using PS Series firmware v10.0 or later. To disable XCopy, use the following ESX CLI command: esxcli system settings advanced set --int-value 0 --option /DataMover/ HardwareAcceleratedMove Unmapping with VMware In VMWare ESX 5.5u3, automatic unmapping is enabled by default for deletion operations such as deleting or migrating a VM. Space reclamation can be done manually by running the esxcli storage vmfs unmap command. For more information, see Using esccli in vSphere 5.5 to reclaim VMFS deleted blocks on thin-provisioned LUNs. Unmapping with VVol Datastores Unmap SCSI commands enable the EqualLogic array to reclaim the space in a thin volume. Starting with PS Series firmware v10.0, Unmap supports multiple LUNs under a single Protocol Endpoint (PE) target. In a VMware environment, whenever files are deleted or space optimization utilities are run, the guest OS on VVol datastores issues the unmap SCSI commands. Blocks that are not being utilized by the OS are reclaimed. NOTE: • Unmap for VVol datastores requires ESX v6.5 or later. • Unmap is not reported as an available function for VVols until all members in the group are updated to PS Series v10.0. Limitations Unmap support requires the use of the command line utility esxcli in order to perform unmap operations on VMFS Datastores. This includes ESXi v6.5 Datastores. ESXi does not support unmap with PS series arrays in the following three cases: • The EQL volume is replicated. (SYNC or ASYNC). This restriction is true for all operating systems supporting unmap. • The VMFS Datastore was updated from VMFS v3.x to VMFS v5.0. It must be formatted at VMFS v5+ in order to support unmap • ESXi v6.5 offers VMFS automatic unmap on VMFS v6.x Datastores. However, VMware requires that the unmap granularity be 1MB or less. EQL is 15MB. Unmapping Replicated Volumes You should not run operations that result in SCSI unmap operations (for example, format or defrag) on volumes on which replication (including synchronous replication) is enabled. Such operations on replicated volumes result in zeros being written to the destination sectors of the volume. This writing of zeros can cause the operations to take a long time to complete, and no space is reclaimed. Therefore, Dell recommends that you disable 154 About Volumes