Hub/Switch Installation Guide

Chapter 3 System Preparation
HPSS Installation Guide September 2002 157
Release 4.5, Revision 2
where logicalVolume is a raw logical volume that is sized to provide at least 20 seconds of
I/O throughput.
To measure write performance on a single disk (see warning below):
% iocheck -w -t 20 -b 1mb -o 1mb /dev/r<logicalVolume>
where logicalVolume is a raw logical volume that is sized to provide at least 20 seconds of
I/O throughput.
WARNING: The contents of this logical volume will be overwritten so be sure to use the correct
logical volume name.
3.6.2 Linux
For Linux,verify that there isa raw devicemapping for eachblock device tobe accessed by HPSS.
To list all current device mappings:
% raw -a -q
/dev/raw/raw1: bound to major 8, minor 1
/dev/raw/raw2: bound to major 8, minor 2
Block devices can be mapped to raw devices at boot time by adding mapping information to the
/etc/sysconfig/rawdevices file.To map the firstpartition of SCSI disk a to raw device raw1 andthe
second partition of SCSI disk b to raw device raw2, add the following lines:
/dev/raw/raw1 /dev/sda1
/dev/raw/raw2 /dev/sdb2
Oneach DiskMover node,measurethe rawdisk readandwriteI/OperformanceofallHPSSdisks
and verify that they are at expected levels.
To measure read performance on a single disk:
% iocheck -r -t 20 -b 1mb /dev/raw/rawX
Where X is the number of the raw device that is sized to provide at least 20 seconds of I/O
throughput.
To measure write performance on a single disk (see warning below):
% iocheck -w -t 20 -b 1mb -o 1mb /dev/raw/rawX
Where X is the number of the raw device that is sized to provide at least 20 seconds of I/O
throughput.
WARNING: The contents of this diskwill be overwrittenso be sure to use thecorrect disk name.