Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide

The following are restrictions for dynamically adding devices to an SRDF consistency group using the symcg modify -add command:

• The symcg modify -add command:
  • Cannot add new SRDF groups to the CG.
  • Cannot add a concurrent R11 device to a CG enabled at the composite group level.
  • Prohibits adding both mirrors of a concurrent R11 device to the same SRDF group name.
  • Cannot add a triangle of devices to a CG. In other words, a concurrent R11 device cannot have one R1 mirror paired with an R21 device, which is then paired with an R22 device that is paired with the other R1 mirror of the concurrent R1 device.
  • Prohibits adding a cascaded R1 device to a concurrent CG.
  • Prohibits adding a concurrent R1 device to a cascaded CG.
• If the target is a cascaded CG, the operation must be enabled by CG hop 1 or by the SRDF group name hop 1.
• If the target is a cascaded CG and the devices to be added are simple R1 devices, the CG cannot be enabled by CG hop 2 or by SRDF group name hop 2.
• If the target is a cascaded CG and the devices to be added are cascaded R1 devices paired with diskless R21 devices, then all R21 devices in the affected SRDF group must also be diskless.
• If the target is a cascaded CG and the devices to be added are cascaded R1 devices paired with non-diskless R21 devices, then all R21 devices in the affected SRDF group must be non-diskless.