IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Chapter 8. Open system servers - Linux for xSeries 301

򐂰 Seeks

Multiple processes do random lseek(). The idea of using multiple processes is to always

have outstanding lseek() requests, so the device (disk) stays busy. Seek time is an

indication of how good your OS can order seeks and how fast your hardware actually can

do random accesses.

8.6.2 Downloading

For downloading Bonnie, go to the following Web site:

http://www.textuality.com/bonnie/download.html

Once there you find the sources of bonnie-1.4, selecting:

򐂰 Source tar ball, gzipped

򐂰 Source tar ball, bzipped2

򐂰 Source RPM (SuSE Linux)

򐂰 i386™ binary RPM (SuSE Linux 7.1+)

򐂰 Alpha binary RPM (SuSE Linux 7.1+)

Installation and compilation should be straightforward. For Linux, your easiest option is to use

rpm --rebuild on the source RPM. If you use Linux (preferably SuSE Linux) with a i386

machine, you can even use the binary RPM.

8.7 Bonnie++

Bonnie++ is a benchmark suite that is aimed at performing a number of simple tests of hard

drive and file system performance. Then you can decide which test is important and decide

how to compare different systems after running it.

The main program tests database type access to a single file (or a set of files if you want to

test more than 1 G of storage), and it tests creation, reading, and deleting of small files that

can simulate the usage of programs such as Squid, INN, or Maildir format e-mail.

The ZCAV program tests the performance of different zones of a hard drive. It does not write

any data (so you can use it on full file systems). It can show why comparing the speed of

Windows at the start of a hard drive to Linux at the end of the hard drive (typical dual-boot

scenario) is not a valid comparison.

Bonnie++ was based on the code for Bonnie by Tim Bray. Go to the following Web site for a

summary of the differences between Bonnie 1.0 and Bonnie++.

http://www.coker.com.au/bonnie++/

The original author (Tim Bray) has also put a description of Bonnie on his pages.

8.8 Disk bottlenecks

As a general rule for Linux performance analysis, the more observable gains with system

performance can be achieved by properly tuning and sizing the memory subsystem, disk

subsystem, and network subsystem, in that order.

The disk subsystem can be the most important aspect of I/O performance, but problems can

be hidden by other factors, such as the lack of memory. Finding disk bottlenecks is easier