User Guide

Consistency Checks

Consistency Check (CC) is a background operation that verifies and corrects the mirror or parity data for

fault tolerant virtual disks. It is recommended that you periodically run a consistency check on virtual

disks.

You can manually start a CC using the BIOS Configuration Utility or the Dell OpenManage storage

management application. You can schedule CC to run on virtual disks using a Dell OpenManage storage

management application. To start a CC using the BIOS Configuration Utility, see the topic Checking

Data Consistency.

Disk roaming

Disk roaming is moving the physical disks from one cable connection or backplane slot to another on the

same controller. The controller automatically recognizes the relocated physical disks and logically places

them in the virtual disks that are part of the disk group. You can perform disk roaming only when the

system is turned off.

CAUTION: Do not attempt disk roaming during RAID level migration (RLM) or online capacity

expansion (OCE). This causes loss of the virtual disk.

Using disk roaming

Perform the following steps to use disk roaming:

1. Turn off the power to the system, physical disks, enclosures, and system components.

2. Disconnect power cables from the system.

3. Move the physical disks to desired positions on the backplane or the enclosure.

4. Perform a safety check. Make sure the physical disks are inserted properly.

5. Turn on the system.

The controller detects the RAID configuration from the configuration data on the physical disks.

FastPath

FastPath is a feature that improves application performance by delivering high I/O per second (IOPs). The

Dell PowerEdge RAID Controller (PERC) H710P and H810 cards support FastPath.

FastPath is a further enhancement of the Cut Through IO (CTIO) feature, introduced in PERC H700 and

PERC H800, to accelerate IO performance by reducing the IO processing overhead of the firmware.

CTIO reduces the instruction count required to process a given IO. It also ensures that the optimal IO

code path is placed close to the processor to allow faster access when processing the IO.

Under specific conditions with FastPath, the IO by-passes the controller cache and is committed directly

to the physical disk from the host memory, through the second core of the dual-core RAID-on-Chip

(ROC) on the controller. FastPath and CTIO are both ideal for random workloads with small blocks.

NOTE: The PERC H310 and PERC H710 do not support FastPath.