Notes on the iostat command, Shown in – HP Hitachi Dynamic Link Manager Software User Manual

Page 671

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Table A-1 Examples of Linux Command Execution Times

Linux

commands

Time

Example 1

#1

Example 2

#2

Before HDLM

installation

After HDLM

installation

Before HDLM

installation

After HDLM

installation

lvmdiskscan

6.1 sec

19.6 sec

3.8 sec

10.6 sec

pvscan

2.6 sec

12.6 sec

1.5 sec

5.2 sec

# 1

CPU: Pentium III 1.4 GHz x 2
Memory: 1 GB
Connection between host and storage systems: 64 LU x 2 paths (total

128 paths)

# 2

CPU: Xeon 2.0GHz x 2
Memory: 2 GB
Connection between host and storage systems: 64 LU x 2 paths (total

128 paths)

Notes on the iostat Command

If an HDLM device is not specified for the iostat command, the HDLM device

will not be displayed. Information about an HDLM device is displayed only

when the HDLM device is specified for the iostat command (in such case as
iostat -x /dev/sddlmaa). The information (CPU or I/O statistics) displayed

for the HDLM device is always 0, and the actual value is displayed for each

SCSI device that conforms to the HDLM device.

If you are going to obtain information about an HDLM device, perform

calculations by using the value of a SCSI device that conforms to the HDLM

device. The following is an example of executing the iostat command.

Figure A-2 Example of Executing the iostat Command

Notes on Linux Commands and Files

A-3

Hitachi Dynamic Link Manager User Guide for Linux

®

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