Platform - Alcatel-Lucent 5620 Troubleshooting Manual

8 — Troubleshooting Solaris and Windows platforms
Procedure 8-3 Problem: There is excess disk activity on my Solaris

platform

In a system with memory bottlenecks, there is a lot of disk activity. Much of this activity
is related to swapping processes in and out of main memory. Swapping is detrimental
to performance because it increases activity without contributing to productivity. This
causes sluggish performance.
Swapping occurs when the active parts of the processes need more memory than the
size of actual memory installed. When this happens, some of the memory contents are
copied to disk and replaced by another process. When the portion of memory that was
copied to disk is required, it is reloaded.
This scenario may continue until the system is no longer running any processes and is
spending almost all of its time copying code and data in and out of main memory.
1
2
3
8-6
The %b and svc_t columns are the key fields to determine whether a disk
bottleneck exists. If the average service time (svc_t) is between 30 and 50 ms, and
the disk (%b) is greater than 20% busy, there is a minor disk loading problem. If
the service times exceed 50 ms, the disk is considered disk or I/O bound.
In the example, the sd3 disk showed 90 percent disk activity in the %b column.
Because disk sd3 is busier than disk sd1, disk performance may be enhanced by
moving data from disk sd3 to disk sd1.
Open a command or shell tool.
To collect data, type:
vmstat s ↵
where s is the time, in seconds, over which you want to collect data. Alcatel-Lucent recommends
that you start with 2 s.
Review the vmstat output. The following is a sample of vmstat data. See Table
for a description of the vmstat report.
#vmstat 2
procs memory
r b w swap free re mf pi po fr de sr s1 s3 - - in sy cs us sy id
0 0 0 45148 16628 0
0 0 0 527060 20548 0
0 0 0 527060 20548 0
Aug 2010
Troubleshooting Guide
page
6 3 1 3 0 1
7 0 0 0 0 0
0 0 0 0 0 0
Alcatel-Lucent 5620 Service Aware Manager, Release
disk faults
0 1 0 0 89 473 192 1 1 98
0 0 0 0 73 280 143 0 0 99
0 0 0 0 18 319 143 0 0100
3HE 05723 AAAD TQZZA Edition 01
8-3
cpu
8.0 R4