Users Guide
Managing storage devices
Beginning with iDRAC 2.00.00.00 release, iDRAC expands its agent-free management to include direct configuration of the new
PERC9 controllers. It enables you to remotely configure the storage components attached to your system at run-time. These
components include RAID and non-RAID controllers and the channels, ports, enclosures, and disks attached to them.
The complete storage subsystem discovery, topology, health monitoring, and configuration are accomplished in the
Comprehensive Embedded Management (CEM) framework by interfacing with the internal and external PERC controllers
through the MCTP protocol over I2C interface. For real-time configuration, CEM supports PERC9 controllers. The firmware
version for PERC9 controllers must be 9.1 or later.
Using iDRAC, you can perform most of the functions that are available in OpenManage Storage Management including real-time
(no reboot) configuration commands (for example, create virtual disk). You can completely configure RAID before installing the
operating system.
You can configure and manage the controller functions without accessing the BIOS. These functions include configuring virtual
disks and applying RAID levels and hot spares for data protection. You can initiate many other controller functions such as
rebuilds and troubleshooting. You can protect your data by configuring data-redundancy or assigning hot spares.
The storage devices are:
● Controllers — Most operating systems do not read and write data directly from the disks, but instead send read and write
instructions to a controller. The controller is the hardware in your system that interacts directly with the disks to write and
retrieve data. A controller has connectors (channels or ports) which are attached to one or more physical disks or an
enclosure containing physical disks. RAID controllers can span the boundaries of the disks to create an extended amount of
storage space— or a virtual disk — using the capacity of more than one disk. Controllers also perform other tasks, such as
initiating rebuilds, initializing disks, and more. To complete their tasks, controllers require special software known as firmware
and drivers. In order to function properly, the controller must have the minimum required version of the firmware and drivers
installed. Different controllers have different characteristics in the way they read and write data and execute tasks. It is
helpful to understand these features to most efficiently manage the storage.
● Physical disks or physical devices — Reside within an enclosure or are attached to the controller. On a RAID controller,
physical disks or devices are used to create virtual disks.
● Virtual disk — It is storage created by a RAID controller from one or more physical disks. Although a virtual disk may be
created from several physical disks, it is viewed by the operating system as a single disk. Depending on the RAID level used,
the virtual disk may retain redundant data if there is a disk failure or have particular performance attributes. Virtual disks can
only be created on a RAID controller.
● Enclosure — It is attached to the system externally while the backplane and its physical disks are internal.
● Backplane — It is similar to an enclosure. In a Backplane, the controller connector and physical disks are attached to the
enclosure, but it does not have the management features (temperature probes, alarms, and so on) associated with external
enclosures. Physical disks can be contained in an enclosure or attached to the backplane of a system.
In addition to managing the physical disks contained in the enclosure, you can monitor the status of the fans, power supply, and
temperature probes in an enclosure. You can hot-plug enclosures. Hot-plugging is defined as adding of a component to a system
while the operating system is still running.
The physical devices connected to the controller must have the latest firmware. For the latest supported firmware, contact your
service provider.
Storage events from PERC are mapped to SNMP traps and WSMAN events as applicable. Any changes to the storage
configurations are logged in the Lifecycle Log.
Table 36. PERC Capability
PERC Capability CEM configuration Capable
Controller (PERC 9.1 or later)
CEM configuration Non-capable
Controller (PERC 9.0 and lower)
Real-time If there is no existing pending or
scheduled jobs for the controller, then
configuration is applied.
If there are pending or scheduled jobs
for that controller, then the jobs have to
be cleared or you must wait for the jobs
Configuration is applied. An error
message is displayed. Job creation is not
successful and you cannot create real-
time jobs using Web interface.
13
184 Managing storage devices