Data Center – Staffing Levels

Coastal Technologies, developer of HELP!Desk software, has published guidelines for determining the number of technicians needed to staff a support center.

Establishing the proper support staff to customer ratio is essential for any organization. Each of the factors in the table below has an effect on the staff size. Assume a starting ratio 75 to 100 customers per analyst (75:1 to 100:1), then adjust the ratio for the following conditions:

Consideration	Support Staff Levels
Experienced support staff	Decrease
Customer handling expertise	Decrease
Large number of products to support	Increase
Multiple shifts and weekends	Increase
Support staff possesses knowledge of the organization’s business	Decrease
Internal support only	Decrease
External support only	Increase
Both internal and external support	Increase
Service Level Agreements negotiated	Decrease
Budget concerns	Decrease*
Multiple platforms to support (i.e. Web, PC, Mainframe, Mac)	Increase
Automated tools in place	Decrease
Experienced support center management	Decrease
Support center has good reputation in company	Decrease
Center has bad reputation	Increase
Multiple support center locations	Increase
Quality Assurance or Quality Control responsibility	Increase
Proactive support philosophy	Increase**
Support center has additional responsibilities not listed above	Increase

* = A staffing decrease may be required to meet your budget, but too small a staff can create bigger problems later on – dissatisfied customers, excessive stress, technician burnout and high turnover to name a few.

**= Initially, proactive support requires more staff per customer. The trend is reversed down the line as you should see a decrease in customer problems.

Source: http://coastaltech.com/hd-staff.htm

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/

Benchmarking File Systems and Storage

Avishay Traeger from the IBM Haifa Research Lab and Erez Zadok from Stony Brook University are raising awareness of issues relating to proper benchmarking practices of file and storage systems.  They hope that with greater awareness, standards will be raised, and more rigorous and scientific evaluations will be performed and published.

In May 2008 they published a paper in the ACM Transactions on Storage entitled “A Nine Year Study of File System and Storage Benchmarking’” in which they surveyed 415 file system and storage benchmarks from 106 papers that were published in four highly-regarded conferences (SOSP, OSDI, USENIX, and FAST) between 1999 and 2007.  They found that most popular benchmarks are flawed, and many research papers used poor benchmarking practices and did not provide a clear indication of the system’s true performance.  They have provided a set of guidelines that they hope will improve future performance evaluations. An updated version of the guidelines is available.

Traeger and Zadok have also set up a mailing list for information on future events, as well as discussions.  More information can be found on their File and Storage System Benchmarking Portal
http://fsbench.filesystems.org/.

Help Desk Staffing Ratios by Size and Industry

An ongoing survey by Computer Economics is investigating the level of staffing organizations allocate to their help desks. To date, more than 300 companies of varying size, spanning a wide group of industry sectors, have participated in the ongoing study. The study investigates staffing in terms of the ratio between help desk employees and the total number of employees supported by the help desk.

The study has found that the median staffing ratio is 1.3% (in other words, 13 help desk support personnel are supporting 1,000 company employees, or one help desk headcount for every 76.9 company employees). At the 25th percentile, the ratio is 0.4% and at the 75th percentile, the ratio is 2.8%. As the help desk is usually an overhead function, these moderate ratios show that most organizations are applying their budgets prudently. A median ratio of 1.3% provides an acceptable level of support to the operating staff. The study results indicate that organizational size and industry sector will typically have an impact on the ratio of help desk personnel to total employees.

Source: AFCOM – http://www.afcom.com/The_Association/ResourceCenter/Data_Center_Management/Help_Desk_Staffing.asp

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/

Servers – Mean Time Between Failure and Mean Time to Repair

When investigating the purchase of computer servers it is important to understand the terms “Mean Time Between Failure” (MTBF) and “Mean Time to Repair” (MTTR).  Here is a link to an outstanding article by George Spafford that expains the terms and gives good examples of each.

Understanding ‘Mean Time Between Failure’

May 14, 2004 by George Spafford in Datamation
http://itmanagement.earthweb.com/columns/article.php/3354191

ITIL – Staffing Ratios

ITIL Benchmarks

In a study or 125 companies in the United Kingdom,  researchers found that the “IT Heads in relation to the Number of Users” was a median of 6% for ITIL adopters and 5% for ITIL rejecters.

From the same study, training costs for ITIL adoption were on average £930 per IT head.

Source: ”The ITIL Experience – Has it been worth it?”, Noel Bruton, Bruton Consultancy, Spring 2004. See: http://74.125.47.132/search?q=cache:HIwsdVqpREAJ:www.aaromba.com/assets/pdf/whitepapers/The-ITIL-Experience.pdf+ITIL+Experience+-+Has+it+been+worth+it%3F&hl=en&ct=clnk&cd=1&gl=us

Benchmark: Ratio of Analysts to Programmers

According to Tim Bryce (Managing Director of M. Bryce & Associates),

If systems analysis is performed correctly, programmer productivity should improve as analysts should be providing good specifications for application assignments. In the absence of systems analysts, considerable time is lost by the programmer who has to second-guess what the end-user wants. Inevitably, this leads to rewriting software over and over again. Good data and processing specs, as provided by a systems analyst, will improve programmer productivity far better than any programming tool or technique. This means programmers are the beneficiaries of good systems analysis.

This brings up an interesting point, what should be the ratio of Systems Analysts to Programmers in a development organization? Frankly, I believe there should be twice as many analysts than programmers. By concentrating on the upfront work, programming is simplified.

Source: Bryce, Tim, “The Ratio of Analysts to Programmers”, Toolbox for IT, August 24, 2006.

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.

IT Staff to User Ratio – Additional Numbers

A recent posting on the Spiceworks Community forum revels IT staff to user ratios ranging from 100:1 to 20:1 based upon different factors such as number of different locations, hardware and software diversity, proficiency of the users, hours for direct support, help desk availability, etc. The best posting came from Eric Osterholm. He reported:

“Awhile back I worked for a great Consulting Company called Collective Technologies (a spinoff from Pencom Systems); at it’s height, there were over 350 Consultants in the field. The topic of this ratio came up time and time again…

Based on what we saw at our client sites, the consensus was that a helpdesk (someone else doing servers and network) ratio was about 100:1 with proper automation technologies (imaging\patching\helpdesk\etc). For admins supporting servers and helpdesk, the ratio closed to 50:1. For those supporting everything, the numbers were all over the board… from 100:1 to 20:1. The one constant we saw was that the more mature shops adopted automation tools to make their current staff more efficient, reducing these ratios.”

The entire forum post can be found at: http://community.spiceworks.com/topic/7870?query=ratio+of+users+it