Uptime Information
Uptime is a measure of the time a machine has been up without any downtime.
Htop adds an exclamation mark when uptime is bigger than 100 daysIt is often used as a measure of computer operating system reliability or stability, in that this time represents the time a computer can be left unattended without crashing, or needing to be rebooted for administrative or maintenance purposes.
Conversely, long uptime may indicate negligence, because some critical updates can require reboots on some platforms.[1]
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Records
In 2005, Novell reported a server with a 6 year uptime.[2][3]
Netcraft maintains the uptime records for many thousands of web hosting computers.[4]
Determining system uptime
Microsoft Windows NT
Using systeminfo
Users of Windows XP Professional, Windows Server 2003 and Windows Vista systems can type systeminfo at the Command Prompt to display all system information, including the System Up Time.[5]
C:\> systeminfo | find "Time:" System Up Time: 0 Days, 8 Hours, 7 Minutes, 19 Seconds
Note: Windows Vista Business 64-bit and Windows 7 do not return a "System Up Time" but "System Boot Time" instead. Also note that the exact text and date format is dependent of the language and locale, Windows is running.
Using net statistics server/workstation
C:\> net statistics workstation | find "since" Server Statistics for \\COMPUTERNAME Statistics since 8/31/2009 8:52:29 PM
The line that start with "Statistics since ..." provides the time that the server was up from. The command "net stats srv" is shorthand for "net statistics server."[6] The exact text and date format is dependent of the language and locale, Windows is running.
Using Uptime.exe
Microsoft has also provided a downloadable Uptime.exe utility:
C:\> Uptime SYSTEMNAME has been up for: 2 day(s), 4 hour(s), 24 minute(s), 47 second(s)
Using WMI
Uptime can also be determined via Windows Management Instrumentation from the command-line with WMIC:
C:\> wmic os get lastbootuptime LastBootUpTime 20110508161751.822066+060
The timestamp is in the format yyyymmddhhmmss.nnn, so this is a computer that last booted up on 8 May 2011 at 16:17:51.822. WMI can also be used to find the boot time of remote computers as well (Windows permissions allowing), for example with WMIC:
C:\> wmic /node:"my-server" os get lastbootuptime LastBootUpTime 20101219141712.462006+060
The text "LastBootUpTime" and the timestamp format are always the same regardless of the language and locale, Windows is running.
WMI can also be used via a programming language such as VBScript or Powershell[7][8]
Using Windows Task Manager
Windows 7 Task Manager Performance tab screenshot.Users of Windows Vista and Windows 7 can see uptime in Windows Task Manager under the tab Performance.
Linux
Using uptime
Users of Linux systems can use the uptime utility (uptime(1) – Linux User Commands Manual) to get the uptime, together with the current time, the number of users and load averages for the past 1, 5 and 15 minute intervals:
$ uptime 18:17:07 up 68 days, 3:57, 6 users, load average: 0.16, 0.07, 0.06
Using /proc/uptime
Shows how long the system has been on since it was last restarted:
$ cat /proc/uptime 350735.47 234388.90
The first number is the total number of seconds the system has been up. The second number is how much of that time the machine has spent idle, in seconds.[9] On multi core systems (and some linux versions) the second number is the sum of the idle time accumulated by each CPU.[10]
BSD
Using uptime
Like Linux, BSD based operating systems such as FreeBSD and Mac OS X also have the uptime command (See uptime(1) – FreeBSD General Commands Manual).
Using sysctl
There is also a method of using sysctl to call the system's last boot time[11]:
$ sysctl kern.boottime
kern.boottime: { sec = 1271934886, usec = 667779 } Thu Apr 22 12:14:46 2010
OpenVMS
Users of OpenVMS systems can type show system at the command prompt.[12]
$ show system/noprocess OpenVMS V7.3-2 on node JACK 29-JAN-2008 16:32:04.67 Uptime 894 22:28:52
This shows the uptime as days then hours:minutes:seconds.
External Uptime Measuring
There are a many external services which can be used to monitor the uptime and downtime as well as availability of a service or a host. Some examples:
See also
| Look up uptime in Wiktionary, the free dictionary. |
References
- ^ How to install Windows Updates with only one reboot
- ^ Marathon servers: Novell shows off servers with longest uptime
- ^ Uptime Workhorses: Still Crazy after all these Years
- ^ Netcraft: Sites with longest running systems by average uptime in the last 7 days
- ^ Tracking down uptime in Windows XP
- ^ How to find Windows uptime?
- ^ How Can I Tell if a Server has Rebooted?
- ^ How Can I Determine the Uptime for a Server?
- ^ Reference Guide For Red Hat Enterprise Linux 4.5 - 5.2.30. /proc/uptime
- ^ See comments to the patch
- ^ sysctl(8) Mac OS X Manual Page
- ^ PARSEC Group - Undocumented OpenVMS Features
- ^ 10 Free Services to Monitor Your Site’s Uptime
- ^ Robin Wauters (19 January 2010). "WatchMouse Monitors 26 Popular APIs So You Don't Have To". Techcrunch. http://techcrunch.com/2010/01/19/watchmouse-api-status/. Retrieved 21 April 2011.
- ^ Wikimediafoundation.org
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Categories:
- Real-time computing
- Unix user management and support-related utilities
- Fault-tolerant computer systems
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