Chapter 3 System Preparation
HPSS Installation Guide September 2002 157
Release 4.5, Revision 2
wherelogicalVolume 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>
wherelogicalVolume 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
ForLinux, verify that there is a raw device mapping for each block device to be 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/rawdevicesfile. To map the first partition of SCSI disk ato raw device raw1 and the
second partition of SCSI diskb to raw device raw2, add the following lines:
/dev/raw/raw1 /dev/sda1
/dev/raw/raw2 /dev/sdb2
Oneach Disk Mover node, measure the raw disk read and write I/O performance of all HPSS disks
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 disk will be overwritten so be sure to use the correct disk name.