Integrated Dell Remote Access Controller 9 User's Guide

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OCE and RLM Restrictions or Limitations

Following are the common limitations for OCE and RLM:

OCE/RLM is restricted to the scenario where the disk group contains only one VD.
OCE is not supported on RAID50 and RAID60. RLM is not supported on RAID10,RAID50 and RAID60.
If the controller already contains the maximum number of virtual disks, you cannot perform a RAID level migration or capacity expansion on any virtual disk.
The controller changes the write cache policy of all virtual disks undergoing a RLM/OCE to Write-Through until RLM/OCE is complete.
Reconfiguring Virtual Disks typically impacts disk performance until the reconfiguration operation is complete.
The total number of physical disks in a disk group cannot exceed 32.
If any background operation (like BGI/rebuild/copyback/patrol read ) is already running on the corresponding VD/PD then Reconfiguration (OCE/RLM) is not allowed at that time.
Any kind of disk migration when Reconfiguration (OCE/RLM) is on progress on drives associated with VD causes reconfiguration to fail.
Any new drive added for OCE/RLM becomes part of the VD after reconstruction completes. But State for those new drive changes to Online just after reconstruction starts.