Using WLM to Estimate Memory Requirements

Audience: System Administrators

Date: May 13, 2001

AIX 4.3.3 Work Load Manager is normally used to allocate CPU and Memory by application/user. It can also be used to estimate memory requirements. The steps include:

1. Create a unique WLM class for the desired workload (smitty wlm)
2. Start WLM in the passive mode ("wlmcntrl -p")
3. Monitor utilization (wlmstat )

The output will look something like below:

# wlmstat 1 3
	Name 			CPU 	MEM
	Unclassified 		0 	2
	System 			0 	52
	Default 		0 	2
	test 			0 	0
	test1 			12 	21
	Shared 			0 	23

	Name 			CPU 	MEM
	Unclassified 		0 	2
	System 			0 	51
	Default			0	2
	test 			0 	0
	test1 			12 	22
	Shared 			0 	23

CAVEAT: File pages that are used by more than one class will be listed in the "shared" class.

Other commonly used AIX memory monitoring tools include: vmstat, ps, topas, svmon, See the AIX documentation for more information.

PS Thanks to Harold Lee from IBM's Advanced Technical Support, from whom I shamelessly plagiarized this tip.