ASRock X79 Extreme11 LSI SAS2 Integrated RAID Solution User Guide - Page 12

Chapter 2: Overview of Integrated RAID Mirrored Volumes

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Mirrored Volume Features

SAS2 Integrated RAID Solution User Guide

Page 12

LSI Corporation Confidential

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August 2010

2.4.6

Disk Write Caching

By default, the Integrated RAID firmware disables disk write caching for mirrored

volumes. It does this to ensure that the write journal entry stored in nonvolatile static

RAM (NVSRAM) is always valid. If you enable disk write caching (not recommended),

you may cause the disk write log to be invalid.

2.4.7

NVSRAM Usage

The Integrated RAID firmware requires at least a 32-KB NVSRAM to perform write

journaling for mirrored volumes on LSI SAS2 controllers. The NVSRAM also preserves

configuration information across reboots. The firmware uses write journaling to verify

that the disks in the mirrored volume are synchronized with each other.

2.4.8

Background Initialization

Background initialization (BGI) is the process of copying data from primary to

secondary disks in a mirrored volume. The Integrated RAID firmware starts BGI

automatically as a background task when it creates a volume. The volume remains in

the Optimal state while BGI is in progress.

2.4.9

Consistency Check

A consistency check is a background process that reads data from primary and

secondary disks in a mirrored volume and compares it to make sure the data is identical

on both disks. You can use the LSI SAS2 BIOS Configuration Utility to run a consistency

check on a mirrored volume.

2.4.10

Make Data Consistent

If it is enabled in the Integrated RAID firmware, the make data consistent (MDC) process

starts automatically and runs in the background when you move a redundant volume

from one SAS controller to another SAS controller. MDC compares the data on the

primary and secondary disks. If MDC finds inconsistencies, it copies data from the

primary disk to the secondary disk.

Section	Page
SAS2 Integrated RAID Solution User Guide	1
Introduction to the Integrated RAID Solution	5
1.1 Overview	5
1.2 Benefits and Features	6
1.2.1 Host Interface	6
1.2.2 Metadata Support	6
1.2.3 SMART Support	6
1.2.4 Fusion-MPT Support	6
Overview of Integrated RAID Mirrored Volumes	7
2.1 Introduction	7
2.2 Integrated Mirroring and Integrated Mirroring Enhanced Features	7
2.3 Operation of Mirrored Volumes	8
2.4 Mirrored Volume Features	11
2.4.1 Resynchronization with Concurrent Host I/O Operation	11
2.4.2 Hot Swapping	11
2.4.3 Hot Spare Disk	11
2.4.4 Online Capacity Expansion	11
2.4.5 Media Verification	11
2.4.6 Disk Write Caching	12
2.4.7 NVSRAM Usage	12
2.4.8 Background Initialization	12
2.4.9 Consistency Check	12
2.4.10 Make Data Consistent	12
Creating Mirrored Volumes	13
3.1 Mirrored Volume Configuration Overview	13
3.2 Creating Mirrored Volumes	13
3.2.1 Creating an Integrated Mirroring Volume	14
3.2.2 Creating an Integrated Mirroring Enhanced or Integrated Mirroring + Striping Volume	15
3.2.3 Expanding an Integrated Mirroring Volume with OCE	16
3.3 Managing Hot Spare Disks	17
3.3.1 Creating Hot Spare Disks	17
3.3.2 Deleting Hot Spare Disks	18
3.4 Other Configuration Tasks	19
3.4.1 Viewing Volume Properties	19
3.4.2 Running a Consistency Check	19
3.4.3 Activating an Array	20
3.4.4 Deleting an Array	20
3.4.5 Locating Disk Drives in a Volume	21
3.4.6 Selecting a Boot Disk	21
Overview of Integrated Striping	23
4.1 Introduction	23
4.2 Integrated Striping Features	23
4.3 Integrated Striping Description	24
Creating Integrated Striping Volumes	25
5.1 Integrated Striping Configuration Overview	25
5.2 Creating Integrated Striping Volumes	25
5.3 Other Configuration Tasks	27
5.3.1 Viewing Volume Properties	27
5.3.2 Activating an Array	27
5.3.3 Deleting an Array	28
5.3.4 Locating Disk Drives in a Volume	28
5.3.5 Selecting a Boot Disk	29
Using the SAS2 Integrated RAID Configuration Utility	31
A.1 Hardware and Software Requirements	31
A.1.1 Controller Support	31
A.1.2 Operating System and Software Support	32
A.2 Interface Description	32
A.3 Commands	32
A.3.1 Common Command-Line Parameters	33
A.3.2 CREATE Command	33
A.3.3 DELETE Command	35
A.3.4 DISPLAY Command	35
A.3.5 HOTSPARE Command	37
A.3.6 STATUS Command	38
A.3.7 LIST Command	39
A.3.8 MFGPAGE Command	40
A.3.9 CONSTCHK Command	40
A.3.10 ACTIVATE Command	40
A.3.11 LOCATE Command	41

ASRock X79 Extreme11 LSI SAS2 Integrated RAID Solution User Guide - Page 12

Disk Write Caching, NVSRAM Usage, Background Initialization, Consistency Check, Make Data Consistent

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