Dybdahl, Re: Uptimes of Internet Servers.
Here is some information as to why GNU/Linux is missing from the longest uptimes:
According to a separate uptime study by Netcraft, OSS/FS does very well; as of August 3, 2001, of the 50 sites with the highest uptimes, 92% use Apache and 50% run on OSS/FS operating systems. Netcraft keeps a track of the 50 often-requested sites with the longest uptimes at uptime.netcraft.com. Looking at the August 3, 2001 uptime report, I found that 92% (46/50) of the sites use Apache; one site's web server was unknown, and three others were not Apache. Of those three, only one reported to be Microsoft IIS, and that one instance is suspicious because its reported operating system is BSD/OS (this apparant inconsistency can be explained in many ways, e.g., perhaps there is a front-end BSD/OS system that ``masks'' the IIS web site, or perhaps the web server is lying about its type to confuse attackers). In this snapshot, 50% (25/50) ran on an open source operating system, and only Unix-like operating systems had these large uptimes (no Windows systems were reported as having the best uptimes). As with all surveys, this one has weaknesses, as discussed in Netcraft's Uptime FAQ. Their techniques for identifying web server and operating systems can be fooled. Only systems for which Netcraft was sent many requests were included in the survey (so it's not ``every site in the world''). Any site that is requested through the ``what's that site running'' query form at Netcraft.com is added to the set of sites that are routinely sampled; Netcraft doesn't routinely monitor all 22 million sites it knows of for performance reasons. Many operating systems don't provide uptime information and thus can't be included; this includes AIX, AS/400, Compaq Tru64, DG/UX, MacOS, NetWare, NT3/Windows 95, NT4/Windows 98, OS/2, OS/390, SCO UNIX, Sony NEWS-OS, SunOS 4, and VM. Thus, this uptime counter can only include systems running on BSD/OS, FreeBSD (but not the default configuration in versions 3 and later), recent versions of HP-UX, IRIX, GNU/Linux 2.1 kernel and later (except on Alpha processor based systems), MacOS X, recent versions of NetBSD/OpenBSD, Solaris 2.6 and later, and Windows 2000. Note that Windows NT systems cannot be included in this survey (because their uptimes couldn't be counted), but Windows 2000 systems are included in this survey. Again, no Windows system actually made it into the top 50 for uptimes in this snapshot. Note that HP-UX, (many versions of) GNU/Linux, Solaris and recent releases of FreeBSD cycle back to zero after 497 days, exactly as if the machine had been rebooted at that precise point. Thus it is not possible to see an HP-UX, (most) GNU/Linux, or Solaris system with an uptime measurement above 497 days, and in fact their uptimes can be misleading (they may be up for a long time, yet not show it). Still, this survey does compare Windows 2000, GNU/Linux (up to 497 days usually), FreeBSD, and several other operating systems, and a vast number of web servers, and OSS/FS does quite well.
Note that the top 50 longest uptimes at Netcraft are all longer than 497 days. BTW, I always enjoy your informative, polite, and well-reasoned posts.
Regards,
dwheeler.com |