Performance Monitoring and Tuning in AIX

Performance Monitoring :

1. How to find out the system-wide memory usage ?
# svmon -G -i 2 5

2. How to list top 10 memory consuming processes ?

You can use any of the below commands
# svmon -Put 10
# ps aux head -1; ps aux sort -rn +3 head

3. How to list top 10 cpu consuming processes ?

# ps aux head -1; ps aux sort -rn +2 head -10

4. What is the best command for general performance monitoring :

# topas

You can even use 'jtopas', which is a java based system monitoring tool.

5. How to start trace for the entire system ?

# trace -a

6. How to stop trace ?

# trcstop

7. Where is the log file for trace tool located ?

/var/adm/ras/trcfile

8. What is the command used to generate trace report from a trace log file ?

# trcrpt

9. How to generate report on utilization statistics related to an LPAR ?

# lparstat

10. How to display the LPAR configuration report ?

# lpstat -i

11. What are the mostly used commands to find the cpu, memory,disk i/o statistics ?

# sar -> CPU, Memory statistics
# vmstat -> CPU, Memory statistics
# iostat -> CPU, Disk I/O satistics
# topas -> CPU, Memory, Network and Disk I/O statistics
# ps aux -> CPU, Memory statistics

12. How to display processes related to a specific user ?

# ps -fu username

13. How to list all the 64bit processes running in a system ?

# ps -efM

14. How to enable Interface Specific Network Options in AIX ?
# no -o use_isno=1

By enabling use_isno option, you can set buffer settings on a specific interface, giving you better control over performance management of network interfaces.

15. What is 'thewall' and how to set ?
'thewall' in AIX defines the upper limit for network kernel buffers.

When running AIX 5L V5.3 running a 32 bit kernel is 1GB or half the size of real memory depending on which of the two is the smallest. If you have AIX 5L V5.3 running a 64bit kernel the size of thewall will be 65GB or half the size of real memory, depending on which of the two is smaller.
To display the size of the thewall,

# no -o thewall

Note:
the size of thewall is static from AIX 5L Version 5.1 and later, and cannot be changed, to reduce the upper limit of memory used for networking make use of the maxmbuf tunable.

16. What is maxbuf tunable variable and how to set it ?

The maxmbuf tunable used by AIX specifies the maximum amount of memory that can be used by the networking subsystem.

It can displayed by using the below command,
# lsattr -El sys0 -a maxbuf

By default the maxmbuf tunable is disabled, it is set to 0, this means that the value of thewall will be used to define the maximum amount of memory used for network communications. By setting a non zero value to maxmbuf will override the value of thewall. This is the only way of reducing the value set by thewall.

The value of maxbuf's is defined by 1Kb units. To set its value to 1GB,
# chdev -l sys0 -a maxmbuf=1000000

17. How to find out the media speed of a network interface ?

# netstat -v ent0 grep Media

18. How to view the statistics for a specific network adapter ?

# entstat -d ent1

You can also use "netstat -v ent1".

19. How to reset the above network statistics ?

# entstat -r ent1

20. How to start iptrace on a specific network adapter ?

To Start :
# startsrc -s iptrace -a "-i en0 iptrc.out" &

To Stop:
# stopsrc -s iptrace

21. How to generate report from the iptrace's output file ?

# ipreport -r -s iptrc.out > ipreport

22. How to get the NFS statistics ?

NFS server RPC statistics : # nfsstat -sr
NFS server NFS statistics : # nfsstat -sn
NFS client RPC statistics : # netstat -cr
NFS client NFS statistics : #netstat -cn
Statistics on mounted file systems : # nfsstat -m
To reset the nfsstat statistics : # nfsstat -z

23. How to list the current values of all the network tunables?

# no -a

24. How to display the current value of a specific network tunable?

# no -o tcp_recvspace

25. How to display all the values (current, default, boot, min, max..) values of a network tunable ?

# no -L tcp_recvspace

26. What is the file that holds the next boot tunables's values ?

/etc/tunables/nextboot

27. What is the file that automatically generated with all the values of the network tunables that were set immediately after the reboot ?

/etc/tunables/lastboot

28. How to change the current value of a network tunable's value as well as add the entry to the /etc/tunables/nextboot file ?

Use the 'p' flag in the no command.

For Ex., # no -p -o tcp_recvspace=16k

29. How to display all the NFS network variables ?

# nfs -a

30. How to enable the collection of disk input/output statistics ?

# chdev -l sys0 -a iostat=true

31. How to display the 5 busiest logical volumes in a VG ?

# lvmstat -v datavg -c 5

32. How to display, enable and disable the statistics collection for a VG ?

To enable: # lvmstat -v datavg -e
To disable: # lvmstat -v datavg -d
To show : # lvmstat -v datavg

33. How to display the statistics for a LV ?

# lvmstat -l lv001

34. How to report disk statistics ?

# sar -d 5 60
Abovc command displays the disk i/o statistics 60 times in 5 sec interval.

35. How to list top 10 real memory consuming processes ?

# svmon -Put 10

36. How to list top 10 paging space consuming processes ?

# svmon -Pgt 10

37. How to list the files opened by a process ?

# svmon -pP Process_id

38. How to find out the memory usage of a specific process ?

# svmon -wP

39. How to display the paging (swap) usage ?

# swap -s allocated = 4718592 blocks used = 1475527 blocks free = 3243065 blocks

#swap -l
device maj,min total free
/dev/paging02 38, 4 4608MB 3166MB
/dev/paging01 38, 3 4608MB 3168MB
/dev/paging00 10, 14 4608MB 3167MB
/dev/hd6 10, 2 4608MB 3167MB

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