Creating RAID6 arrays in the MegaRAID Human Interface Infrastructure (HII) utility - IBM ServeRAID SAS/SATA Controller

Resolving The Problem

Source

RETAIN tip: H211507

Symptom

The Generic RAID6 option is greyed out and unavailable in the MegaRAID Human Interface Infrastructure (HII) Utility in F1 Setup Menu unless there are five (5) or more SATA HDDs (not SSDs) in Unconfigured Good state.

(where RAID = Redundant Array of Independent Disks, SATA = Serial Advanced Technology Attachment, HDD = Hard Disk Drive)

Affected configurations

The system is configured with one or more of the following IBM options:

• ServeRAID M5110 SAS/SATA Controller Card, option part number 81Y4481, any replacement part number
• ServeRAID M5110 SAS/SATA Controller for IBM System x (CTO), any replacement part number
• ServeRAID M5110e SAS/SATA Controller for IBM System x, onboard, any embedded
• ServeRAID M5115 SAS/SATA Controller, option part number 90Y4390, any replacement part number
• ServeRAID M5120 SAS/SATA Controller for IBM System x, option part number 81Y4478, any replacement part number
• ServeRAID M5210 SAS/SATA Controller for IBM System x, option part number 46C9110
• ServeRAID M5210e SAS/SATA Controller for IBM System x, option part number 46C9117

This tip is not system specific.

This tip is not software specific.

The system has the symptom described above.

Solution

The utility will be updated with clear descriptions of the Generic RAID6 option in a future release of MegaRAID firmware.

The target date for this release is scheduled for third quarter 2014.

The file will be available by selecting the appropriate Product Group, type of System, Product name, Product machine type, and Operating system on IBM Support's Fix Central web page, at the following URL:

http://www.ibm.com/support/fixcentral/

Workaround

In the MegaRAID Human Interface Infrastructure (HII) Utility, use the Create RAID - Advanced menu option, not the Generic menu to create a RAID6 array.

Additional information

This limitation exists in all code up to and including 24.0.2-0013 for the M5210/M5210e, and all code up to and including 23.0.16-0027 for the M5110, M5110e, M5115 and M5120.

The Generic menu was used as a recommended-practice guide. RAID6 with fewer than five (5) drives will suffer a performance penalty, so a RAID10 array is recommended.

SAS drives are more robust than SATA drives, therefore RAID6 is not suggested. RAID6 is not seen as optimal for SSD drives since the overhead of calculating parity would greatly impede the performance of the array.

The Generic menu does not support creating a RAID6 on fewer than five (5) SSD or SAS drives. which, users must use the Create RAID - Advanced menu, and not the Generic menu.

The fix will update the configuration utility such that it is clear that what criteria the Generic RAID6 option will utilize.