Proportion of Software Testers to Developers

Cem Kaner, a professor at the Florida Institute of Technology, has done research on the ratio of software testers to software developers. His presentation entitled “Managing the Proportion of Testers to Other Developers” is partially based on a meeting of the Software Test Managers Roundtable (STMR 3) in Fall 2001.

FIT

The study found that:
– There were very small ratios (1-to-7 and less) and very
large ratios (5-to-1).
– Some of each worked and some of each failed.
– Many remembered successful projects with ratios lower than 1-to-1 more favorably than successful projects with larger ratios.

Read the paper to find out why is there such a range of successful ratios, and why test managers be happy with relatively low ratios?

See: http://www.kaner.com/pdfs/pnsqc_ratios.pdf and http://www.kaner.com/

Apache Server – Requests per Second

This post on www.ilovebonnie.net documents some impressive system performance improvements by the addition of Squid Cache (a caching proxy) and APC Cache (opcode cache for PHP).
* Apache is able to deliver roughly 700% more requests per second with Squid when serving 1KB and 100KB images.
* Server load is reduced using Squid because the server does not have to create a bunch of Apache processes to handle the requests.
* APC Cache took a system that could barely handle 10-20 requests per second to handling 50-60 requests per second. A 400% increase.
* APC allowed the load times to remain under 5 seconds even with 200 concurrent threads slamming on the server.
* These two caches are easy to setup and install and allow you to get a lot more performance out of them.

The post has an in-depth discussion and a number of supporting charts. The primary point is how simple it can be to improve performance and scalability by adding caching.

Source: http://www.ilovebonnie.net/2009/07/14/benchmark-results-show-400-to-700-percent-increase-in-server-capabilities-with-apc-and-squid-cache/

Drupal Benchmarked on Amazon ec2

According to a benchmark test run by John Quinn &  Cailin Nelson,

Drupal systems perform very well on amazon ec2, even with a simple single machine deployment. The larger hardware types perform significantly better, producing up to 12,500 pages per minute. this could be increased significantly by clustering as outlined here.  The apc op-code cache increases performance by a factor of roughly 4x.  The average response times were good in all the tests. The slowest tests yielded average times of 1.5s. again, response times where significantly better on the better hardware and reduced further by the use of apc.

Amazon uses Xen based virtualization technology to implement ec2. The cloud makes provisioning a machine as easy as executing a simple script command. when you are through with the machine, you simply terminate it and pay only for the hours that you’ve used. ec2 provides three types of virtual hardware that you can instantiate.

Source: John & Cailin Blog, “lamp performance on the elastic compute cloud: benchmarking drupal on amazon ec2″, January 28, 2008.