13Managing storage devicesBeginning with iDRAC 2.00.00.00 release, iDRAC expands its agent-free management to include direct configuration of the newPERC9 controllers. It enables you to remotely configure the storage components attached to your system at run-time. Thesecomponents 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 ComprehensiveEmbedded Management (CEM) framework by interfacing with the internal and external PERC controllers through the MCTPprotocol over I2C interface. For real-time configuration, CEM supports PERC9 controllers. The firmware version for PERC9controllers 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 (noreboot) configuration commands (for example, create virtual disk). You can completely configure RAID before installing theoperating system.You can configure and manage the controller functions without accessing the BIOS. These functions include configuring virtual disksand applying RAID levels and hot spares for data protection. You can initiate many other controller functions such as rebuilds andtroubleshooting. 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 writeinstructions to a controller. The controller is the hardware in your system that interacts directly with the disks to write andretrieve data. A controller has connectors (channels or ports) which are attached to one or more physical disks or an enclosurecontaining 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 orderto function properly, the controller must have the minimum required version of the firmware and drivers installed. Differentcontrollers have different characteristics in the way they read and write data and execute tasks. It is helpful to understand thesefeatures 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, physicaldisks 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 createdfrom several physical disks, it is viewed by the operating system as a single disk. Depending on the RAID level used, the virtualdisk may retain redundant data if there is a disk failure or have particular performance attributes. Virtual disks can only becreated 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 theenclosure, but it does not have the management features (temperature probes, alarms, and so on) associated with externalenclosures. 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, andtemperature probes in an enclosure. You can hot-plug enclosures. Hot-plugging is defined as adding of a component to a systemwhile the operating system is still running.The physical devices connected to the controller must have the latest firmware. For the latest supported firmware, contact yourservice provider.Storage events from PERC are mapped to SNMP traps and WSMAN events as applicable. Any changes to the storageconfigurations are logged in the Lifecycle Log.182
