You can automatically define transactions in the script to measure a set of
URL interactions. I defined portions of my script as specific transactions to
quantify the performance of my search portion of the script and the URL
interactions in the Windows NT forums. I did this measurement by placing lr_start_transaction("name") and lr_end_transaction("name")
in the script. After the scenario finishes, the analysis starts automatically
and displays the performance for each of my transactions in a graph.
Testing
Mercury Interactive designed Astra SiteTest to run on one testing machine.
You then use this machine to test performance against your Web machine; you
don't need additional client machines or a controller machine. Because of this
simple design, I was ready to immediately start testing after installing the
software. Screen 2 shows the tests that were ready to run.
I used Astra SiteTest on several Web site configurations. The most
interesting test was against a new Web server designed for larger Web sites than
mine. This machine was a quad 200MHz Pentium Pro with 1GB of RAM and eight 4GB
hard disks on a RAID controller. I configured it with NT 4.0 running Internet
Information Server (IIS) 3.0 and SQL Server 6.5. I had planned to replace my two
original Web servers with this machine.
My test revealed that the machine did not perform better than the original
Web servers. This performance was based on response times, number of errors, and
timeouts. In fact, running IIS and SQL together caused worse performance. The
machine timed out on several page requests when tested with 20 vusers. I tried
the test again with 10 vusers. The machine still failed to serve some pages, and
again timed out on requests.
As a result of this test, Astra SiteTest gave me quantifiable data to tell
the machine's manufacturer. The machine did not perform to my expectations or
the manufacturer's claims, even after the manufacturer reconfigured it. Astra
SiteTest proved that the best solution (when my machine is running IIS and SQL
server) is to use two machines: one running IIS and the other running SQL
Server.
A Laudable Product
I loved using Astra SiteTest--thumbs-up to Mercury Interactive. The
documentation is a little thin, but the interface is so easy to use, I didn't
even need the documentation. The product has so many graphs to choose from in
the analysis phase that I had a difficult time deciding which one to use.
However, everything is grouped in logical categories--after I looked at all the
graphs, I knew which one I wanted.
If you are maintaining a Web site, Astra SiteTest is a must-have tool. It
has helped me rethink my Web site strategy and start implementing a design that
will handle traffic volume and growth, before my Web site goes live.
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