Configuring RAID for Optimal Performance Intel® RAID Controller SRCSASJV Intel® RAID Controller SRCSASRB Intel® RAID Controller SRCSASBB8I Intel® RAID Controller SRCSASLS4I Intel® RAID Controller SRCSATAWB Intel® RAID Controller SRCSAS18E Intel® RAID Controller SRCSAS144E Intel® Server System SR2500ALLX (Intel® Integrated RAID) Intel® Server System SR1550ALSAS (Intel® Integrated RAID) Intel® Server Board S5000PSLROMB (Intel® Integrated RAID) Intel® Server System S7000FC4UR (Intel® Int
Overview Configuring RAID for Optimal Performance Revision History Date April, 2008 Revision Number 1.0 Modifications Initial revision September, 2008 1.1 Minor corrections Disclaimers Information in this document is provided in connection with Intel® products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document.
Configuring RAID for Optimal Performance Overview Table of Contents 1. Overview ............................................................................................................................... 3 2. Performance Measurement Tools....................................................................................... 3 2.1 Copying large files ................................................................................................... 3 2.2 Tools without queuing.....................
Overview 1. Configuring RAID for Optimal Performance Overview The target audience for this guide includes users, technical support personnel, and pre-sales personnel who work with Intel® Server RAID products. It is assumed that the reader has a basic understanding of hard-drive operation, RAID operation, and RAID levels. This guide provides information to help achieve optimal performance of a RAID array depending on the RAID level and performance measurement tool used.
Configuring RAID for Optimal Performance 2.3 Performance Measurement Tools IOmeter* IOmeter* (www.iometer.org) is a sophisticated tool that can measure RAID performance, including sequential, random and mixed workloads, adjustable block sizes, and queuing. This tool requires certain level of proficiency to use it. Unfortunately, queuing does not work under Linux with the current IOmeter version 2006.07.27.
Optimal RAID Settings 3. Configuring RAID for Optimal Performance Optimal RAID Settings The following table provides a simplified quick reference for RAID settings for achieving optimal performance depending on the type of application or test. Please refer to the following sections for more details on the meaning and impact of each setting.
Configuring RAID for Optimal Performance Impact of RAID Settings on Performance 4. Impact of RAID Settings on Performance 4.1 Write Policy The Write Policy can have a very big impact on write performance. There are two modes available – Write Back and Write Thru. 4.1.1 Write Back Mode This mode provides better performance in most cases. In Write-Back mode, the RAID controller acknowledges write I/O requests immediately after the data loads into the controller cache.
Impact of RAID Settings on Performance 4.3 Configuring RAID for Optimal Performance Read Ahead Policy The Read Ahead Policy determines whether the RAID controller will read just a block of data that an application has requested, or whether it will read the whole stripe from the hard-drives. This setting can have big impact on read performance. 4.3.1 No Read Ahead (Normal) The RAID controller will read only the block of data that the application has requested.
Configuring RAID for Optimal Performance Other Performance Factors performance. Typically, sequential workloads benefit from using large strip sizes (512 KB or 1 MB). With random types of access, the strip size depends on the typical access block size and on data alignment. For example, if a database is using 16 KB records with 16 KB alignment, the optimal strip size can be 16KB. For file- or web-server a large (512 KB or 1 MB) strip size can be optimal.
Other Performance Factors Configuring RAID for Optimal Performance the requests. Patrol Read settings can be changed in Adapter Properties in RAID BIOS Console or in RAID Web Console. 5.4 Consistency Check Consistency Check is an important function that helps to detect inconsistencies in data stored across hard drives in redundant RAID arrays and to identify possible sources of silent data corruption. Consistency Check generates substantial number of disk requests that may reduce the RAID performance.
Configuring RAID for Optimal Performance 5.8 Other Performance Factors Overheating Overheating can impact hard drive performance. When measuring performance, especially in a lab environment, make sure that the chassis lid is closed and the air flow is sufficient to cool the hard drives.
