Cisco UCS C220M6/C240M6 C-series M6 servers support PCIe SAS316-port storage controllers for Direct Attached Storage. Controllers
support an Autoconfiguration mode in which the state of a newly inserted disk is automatically moved to the Unconfigured-Good
state.
Because of this, you can choose whether or not to use Autoconfiguration by creating a Storage Profile and associating it with
the server. The default is that the automatic configuration feature is disabled, which retains the drive state when the server
is rebooted.
If Autoconfiguration is used, you must select a drive state from one of the following:
-
Unconfigured-Good
-
JBOD
-
RAID0 (RAID0 WriteBack)
This is because the controller firmware changes the behavior of systemPD to EPD-PT. EPD-PT is internally a RAID0 volume without
any drive DDF metadata. The controller stores the metadata for identifying it as a RAID0 volume. The EPD-PT drives are considered
as JBOD drives so the drive status is reported as JBOD and online.
Controller supports the following models:
-
UCSC-RAID-M6T
-
UCSC-RAID-M6HD
-
UCSC-RAID-M6SD
-
UCSX-X10C-RAIDF
The table below shows the behavior of Autoconfiguration in different scenarios.
Autoconfig Mode
|
Reboot/OCR
|
Hotplug
|
User Action
|
Unconfigured-Good (OFF)
|
|
|
Disabling Autoconfig has no impact on the existing configuration
Any JBOD device remains as JBOD across controller boot.
Any Unconfigured-Good remains unconfiguredgood across controller boot.
|
JBOD
|
|
Newly inserted unconfigured device is converted to JBOD.
|
All Unconfigured-Good drives (non-user created) on the controller while running Autoconfig is converted to JBOD.
User created Unconfigured-Good drive remains Unconfigured-Good until next reboot. During reboot Unconfigured-Good gets converted
to JBOD.
|
RAID0 (RAID0 WriteBack)
|
|
Newly inserted unconfigured device is converted to RAID0 WriteBack.
|
All Unconfigured-Good drives (non-user created) on the controller while running Autoconfig is converted to RAID0 WriteBack.
User created Unconfigured-Good remains Unconfigured-Good across controller reboot.
Any RAID0 WriteBack device remains as RAID0 WriteBack across controller reboot.
|
Selecting EPD-PT (JBOD) as the default configuration does not retain the Unconfigured-Good state across host reboot. The drive
state can be retained by disabling the automatic configuration feature. If the Autoconfig option is used, the default automatic
configuration will always mark a drive as Unconfigured-Good.
When Autoconfig is selected, then the drive is configured to the desired drive state, the JBOD and unconfigured drives will
set the drive state accordingly on the next controller boot or OCR,
The following table shows sample use cases for different Autoconfig scenarios.
Use Case Scenario
|
Autoconfig Option
|
Using the server for JBOD Only (for example: Hyper converged, Hadoop data node etc )
|
JBOD
|
Using the server for RAID volume (for example: SAP HANA database)
|
Unconfigured-Good
|
Using the server for Mixed JBOD and RAID volume
|
Unconfigured-Good
|
Using the server for per drive RAID0 WriteBack (for example: Hadoop data node)
|
RAID0 WriteBack
|