Dell Solutions Enabler 10.0.0 TimeFinder/Clone CLI User Guide

TimeFinder clone copy session consistency

The symclone activate command is used with the -consistent option to create clone copies that are consistent with the database up to the point where activation occurs. This feature is implemented using either the Enginuity Consistency Assist (ECS) feature or SRDF/A.

This feature is used to create clone copies that are consistent with the database up to the point in time that the activation occurs. The feature suspends writes to the source devices during the activation. When the activation has completed, writes are resumed and the target device contains a consistent production database copy of the source device at the time of activation.

The ECA feature is used to consistently activate copy sessions across multiple, heterogeneous hosts. ECA requires either a control host with no database, or a database host with a dedicated channel to the gatekeeper devices. In a SAN environment, gatekeepers and data devices may share the same FA port on the array but the gatekeepers must be available on a separate host HBA from the data devices. This requires a dedicated channel from a host HBA to the switch used to access only gatekeepers and not devices that contain host data. In this configuration, write intensive environments SYMAPI are able to freeze and then thaw I/O to the devices in the device group within the ECA window, regardless of the number of outstanding I/Os held by the HBA.

For detailed information on gatekeeper management, refer to the Dell Solutions Enabler Installation Guide.

A device group, composite group, or a device file must be created on the controlling host for the target database to be consistently activated. Device groups can be created to include all of the devices being accessed or defined by database host access.

As shown in the above example, consistent activation of all copy sessions for Hosts A, B, and C can be done with a single command using a device group (ProdAgrp) that includes all devices accessed by the three hosts. However, for consistent activation of copy sessions for a single host (Host A), without affecting other hosts, use a device group that includes only the devices accessed by the single host.