Dell Solutions Enabler 10.0.0 TimeFinder SnapVX CLI User Guide

Because TimeFinder requires that source and target devices be the same size, the GCM (Geometry Compatible Mode) flag can get automatically set on the target device during SnapVX operations. This flag should be cleared on the device before mapping it to a host, otherwise, in order to clear the flag it must be unmapped from the host, which results in a data outage.

The symdev, symdg, symcg, symsg commands have the set/unset -gcm option to set or unset GCM for a device or group. Refer to the Solutions Enabler CLI Reference Guide for more information on using these commands with the -gcm attribute.