Users Guide

Managing storage devices
Beginning with iDRAC 2.00.00.00 release, iDRAC expands its agent-free management to include direct conguration of the new PERC9
controllers. It enables you to remotely congure 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 conguration 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 conguration, CEM supports PERC9 controllers. The rmware 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) conguration commands (for example, create virtual disk). You can completely congure RAID before installing the operating
system.
You can congure and manage the controller functions without accessing the BIOS. These functions include conguring 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 conguring 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 rmware and drivers. In order to function properly, the controller must have
the minimum required version of the rmware and drivers installed. Dierent controllers have dierent characteristics in the way they
read and write data and execute tasks. It is helpful to understand these features to most eciently 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 dened 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 rmware. For the latest supported rmware, contact your service
provider.
Storage events from PERC are mapped to SNMP traps and WSMAN events as applicable. Any changes to the storage congurations are
logged in the Lifecycle Log.
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196 Managing storage devices