1 Overview

The IBM System Verification Test (SVT) objective is to execute a set of test scenarios against a test configuration that contains the key requirements and components that will create a load on a zLinux machine.

This testing used test scripts currently used by the Domino System test team.

One's perception of system quality is governed under the statement of overall system reliability. A widely accepted definition of software reliability is the probability that a computer system performs its destined purpose without failure over a specified time period within a particular execution environment. This execution environment is known formally as the operational profile, which is defined in terms of sets of possible input values together with their probabilities of occurrence. An operational profile is used to drive a portion of the system testing. Software reliability modeling is therefore applied to data gathered during this phase of testing and then used to predict subsequent failure behavior during actual system operations

A reliability test is one that focuses on the extent to which the feature or system will provide the intended function without failing. The goal of all types of testing is the improvement of the reliability program with specific statements about reliability-specific tests. Reliability is the impact of failures, malfunctions, errors and other defect related problems encountered by customers. Reliability is a measure of the continuous delivery of the correct service (and, the time to failure).

SVT's purpose of running Reliability tests was to ascertain the following:

• Data population for all parts of the infrastructure to force set limits to be achieved and passed
• Running sustained reliability scripts at >100% maximum capacity. Assessing :
• Breakpoints
• System stability pre and post breakpoint
• Serviceability
• Forcing spikes and anti-spikes in usage patterns
• Exposing SMTP, IMAP, POP3, Sametime services to 110% of their maximum load
• Flushing out the DB Table spaces to their maximum, proving the maximum, proving ability to recover/get back to a good place when the maximum limits have been exceeded
• Proving serviceability errors and warnings when thresholds are hit

2 Configuration diagram for zLinux configuration

The zLinux configuration the domino system test team used utilized a VM running on an LPAR of a zSeries with a single Domino instance.

The Domino environment consists of a single Domino instance running under a zLinux VM. The server will host 2,000 registered users.

It is generally recommended to use separate file system for Transaction Logging.

The design task was run prior to the start of the test to upgrade the templates. The update task runs for the entire period of the test (until the server is brought down). 

Details of System under Test (SUT)

Dominio

System	IBM System z990 -- 2084-D32
Processor	32 way processor
Memory	160 GB
LPAR	CPs:  8 shared   Memory: 32 G Central Storage, 16 G Expanded Storage
Guest	CPs:  2 virtual Memory:  1 GB
Fiber Channel Adapter	18 shared 2GB FICON adapters
Disk Drive	180 emulated 3390-9 &  16 emulated 3390-3 on multiple DS8000 (roughly 1TB)
First level Operating    system	zVM 5.3
Guest Operating System	RedHat Linux (64bit) Release 5.1
Domino Server	Domino 8.5 Production Build for z Linux (64 bit)

Table 1 shows the resources available in the physical environment.
2.1 Evaluation Criteria

The performance of Domino 8.5 is evaluated under the following criteria:
· Server CPU: The overall CPU of the server will be monitored over the course of the experiment. The aim is for the server CPU not to go above 75% over the course of the experiment allowing the server to function appropriately. It is acceptable for the CPU to occasionally spike at this level for a short period of time, but it must return to a lower level. High CPU results from the server being stressed due to processes running such as compact, fixup or replication or from user load or any other third party programs.
· Domino Processes CPU: The previous metric monitors the overall CPU of the server, however, the CPU consumption of Domino specific processes will also be monitored individually. In this manner the CPU consumption of Domino specific processes may be evaluated.
· Server Memory: The server memory metric represents the amount of physical memory available on the server. If the available memory becomes low the server performance could be compromised.
· Server Disk I/O: The disk is a source of contention when a server is under load and performing a high number of read and write operations. The disk queue length is measured to determine if the disk I/O operations are resulting in a bottleneck for the system performance.
· Network I/O: These metrics monitor the network utilization to ensure the bandwidth consumption is acceptable and that the network is not overloaded.
· Response Times from the End-user Perspective: The server response times for user actions represent how long a single user must wait for a given transaction to complete. This metric captures the user experience of the application with the server. At times, response times will be longer when a server is under load.  When response times increase over an extended period, or persist at high levels (e.g. when a database or view takes longer than 30 seconds to open), they indicate that performance indicators are being hit and detailed analysis must be performed to determine the source of the slowdown and seek remediation.
· Open Session Response Times: In addition to monitoring the individual action response times, the Open session response times will also be evaluated in order to ensure the server remains responsive over the course of the experiment.

2.2 Tools

In order to simulate user activity and capture the evaluation metrics discussed in section 2.1 a number of tools must be used:

· Server.Load: The Server.Load is a capacity-planning tool that is used to run tests against a targeted Domino server to measure server capacity and response metrics.
· Domino showstats data: The Domino showstats captures important server metrics. A Testnsf client driver may be used to execute the showstats console command at regular intervals for each server in the configuration and will provide Domino-specific data. The resulting data is logged in a text file and may be graphed for analysis.
· Open session: The Open session tool measures mail file request/response times. It will open a view of a mail database at a set time interval and record the response time in milliseconds. As a result, a server slow down may be identified by analyzing the resulting response times.
· NMON Collection Services: This is used to graph the CPU Usage, Disk IOP Utilization and Lan Utilization during the 7 day run.

2.3 Evaluation Process

The server.load tools will be used to place load on the Domino server.  In order to simulate realistic load on the Domino server a total of 5 client drivers running server.load will be used.

The DWA test will run 24 hours per day for 7 days, while the 8.5 Mail script will start at 8.00 AM and will stop at 6.00 PM. There will be a ramp up and ramp down period of one hour. This replicates a real scenario within a company.

The Mail script was replaced with Mail and Sametime for a second evaluation run.

In order to isolate the performance of the Domino server under load from a single user perspective for standard Notes mail, a client driver will execute a “single user” server.load script.

The results represent a single user experience of how the application will perform at busy times of the day when the server is heavily loaded.
 

2.4 Scenario: Online Mode

The scenario evaluates the performance of Lotus Notes Clients in online mode. Online mode means that the user mail files are stored and maintained on the Domino server. Every time a user performs an action the request is sent to the server and the mail file is modified and updated on the server side.

Table 2 shows the action workload of the built in N85Mail script with modifications to the attachment size. The script reflects the workload that is expected of a single user over the course of a day.

The resulting mail distribution is shown in table 3.

The mail with Sametime scripts utilizes the same actions as the 85mail scripts so that action count and mail distribution results are identical to these displayed in tables 3 and 4.

Table 4 shows the action workload of the built in N85DWA script with modifications to the attachment size. The script reflects the workload that is expected of a single user over the course of a day.

The resulting mail distribution is shown in table 5.

3 Test drivers

The workload is generated by five “driver” workstations:
· Driver1
· Driver2
· Driver3
· Driver4
· Driver5

There is an additional client used for a Lotus Notes Administration client and for running statistics collection and monitoring delays in opening databases routinely on each Domino partitioned server.

4 Conclusion and Summary

The test results demonstrate that the zLinux machine configured as described in this report was able to support up to 1600 concurrent, active Notes 8.5.1 users per Domino Server with an average response time below 1 second.

The addition of other application workloads will affect the number of users supported as well as the response time.

Achieving optimum performance in a customer environment is highly dependent upon selecting adequate processor power, memory and disk storage as well as balancing the configuration of that hardware and appropriately tuning the operating system and Domino software.

5 Configuration settings

Server Notes.ini

The following notes.ini variable was added to each of the Domino Servers:

RM_NO_LOG_OBJECTS_IN_MAILBOX=1                        (to prevent mail being transactionally logged while passing through the mail.box)
SCHEDULE_NO_CALCSTATS=1                                           (to disable the hourly statistics collection by the Scheduler task)
IOCP_Disable_Async_Notification=1                                     (to prevent notification of new mail to client drivers)
CREATE_R85_DATABASES=1                                               (to enable ODS 51 as the default)
CREATE_R85_LOG=1                                                               (to enable the creation of Transaction Logs in 85 format)