The Dell 13th generation PowerEdge servers supports a new internal storage topology, where two storage controllers (PERCs) can be connected to a set of internal drives through a single expander. This configuration is used for high performance mode with no failover or High Availability (HA) functionality. The expander splits the internal drive array between the two storage controllers. In this mode, virtual disk creation only displays the drives connected to a particular controller. There are no licensing requirements for this feature. This feature is supported only on a few systems.
iDRAC allows the split mode setting if the expander has the capability to support the configuration. Ensure that you enable this mode prior to installing the second controller. iDRAC performs a check for expander capability prior to allowing this mode to be configured and does not check whether the second PERC controller is present.
To modify the setting, you must have Server Control privilege.
If any other RAID operations are in pending state or any RAID job is scheduled, you cannot change the backplane mode. Similarly, if this setting is pending, you cannot schedule other RAID jobs.
Any change in this setting only takes effect after a system power reset. If you change from Split mode to Unified, an error message is displayed on the next boot as the second controller does not see any drives. Also, the first controller will see a foreign configuration. If you ignore the error, the existing virtual disks are lost.