Institute for Advanced Professional Studies

2010-2011 Server OS Reliability Survey*



For the third year in a row, IBM's AIX UNIX operating system (OS) running on the company's Power System servers scored the highest reliability ratings among 19 different server OS platforms - including other UNIX variants, Microsoft's Windows Server, Linux distributions and Apple's Mac OS X.

Over three-quarters, 78% of survey respondents indicated they experienced less than one of the most common, minor Tier 1 incidents per server, per annum on IBM's AIX v. 5.3 and AIX v. 7.1 distributions.

Those are the results of the joint GFI/Sunbelt Software and ITIC 2010-2011 Global Server Hardware and OS Reliability Survey. The independent Web-based survey polled C-level executives and IT managers at 468 corporations from 23 countries worldwide from November 2010 through January 2011.

The survey data indicated that the reliability and uptime of all the major server OS and server hardware distributions has improved significantly over the past several years.

Microsoft's Windows Server 2008 and Windows Server 2008 R2 served up the biggest surprise in the survey, scoring impressive reliability gains and making it one of the top three most reliable, mainstream server OSs. Windows Server 2008 R2's reliability renaissance is especially impressive since Microsoft's Windows Server OS noticeably lagged behind the majority of the UNIX, Linux and Open Source distributions in ITIC's 2008 and 2009 Server Reliability surveys. This was particularly evident when it came to chronicling the most severe Tier 3 outages, which typically last for four or more hours, involve data loss, and require multiple members of the IT department to perform remediation.

An overwhelming 92% majority of Windows Server 2008 R2 users experienced less than one or one Tier 3 outage per server, per annum followed closely by the 90% of respondents using IBM's AIX 7.1 who said they experienced one or less than one severe Tier 3 incident, per server per annum. Some 86% of Novell SuSE Linux Enterprise Server 11 and 84% of Hewlett-Packard's HP-UX 11i v3 users also testified to the reliability of those platforms, reporting that they experienced either one or less than one unplanned Tier 3 outage per server, annually.

The survey found that all server OSs continue to make year-over-year reliability gains. The essay comment and first person customer interviews revealed that the majority of the moderate and severe Tier 2 and Tier 3 outages were attributable to integration and interoperability issues such as incompatible drivers, trouble applying patches (particularly in highly-customized environments), misconfigurations, and the lack of a specific component or software fix for a particular platform.

IBM hardware was also best in class in terms of reliability, stability and performance. IBM's System z mainframes recorded the least amount of downtime; 76% indicated System z machines experienced just one-to-five minutes of unplanned outages per server, per year, the equivalent of 99.999% or better availability.

Stratus Technologies' ftServer 6300 and 4500 series and Fujitsu's PRIMEQUEST and PRIMERGY Servers also made impressive showings. Some 75% of Stratus ftServer 6300 and 4500 users said they experienced one-to-five minutes of per server, per annum downtime, for five nines of availability. Some 74% of Hewlett-Packard's Integrity and Fujitsu's PRIMEQUEST and PRIMERGY server users said they experienced five minutes or less of unplanned annual server downtime.

Among the other survey highlights:

  • A 57% majority of respondents said their server hardware is between one and three years old. One-in-five corporations - 20% - said their servers were three-to-four years old.
  • One-quarter - 25% of businesses refresh their main line of business server hardware "as needed" and 10% said they upgrade a portion of their servers annually.
  • Only a very small 2% minority of organizations aggressively upgrade their servers every two years. The majority of companies are on a three, four or five year server refresh cycle with 15% of participants stating they upgrade servers every two years; 15% upgrade every three years and 17% are on a protracted five or six year server upgrade cycle. Another 15% said they have "no specific" server upgrade timetable.

By Laura DiDio, Principal
Information Technology Intelligence Consulting (ITIC)

Posted: January 28, 2011

*Excerpts from a copyrighted newsletter prepared by the staff of WServerNews and distributed by IAPS with their permission. The views expressed in the above excerpts were drawn solely by WServerNews or ITIC and do not necessarily reflect the views of IAPS.



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