wanted - opinions on dangers of daily shutdown of Linux

wanted - opinions on dangers of daily shutdown of Linux

Post by Michael Winte » Fri, 25 Feb 1994 07:44:54



From talking with two Unix gurus I have heard conflicting viewpoints of
whether it is dangerous to go through the Linux shutdown procedures on
a frequent basis (i.e. daily).  I realize from reading the FAQs that there
are utilities that you run to shut down your machine and you don't just
shut the power down without killing processes etc...  So, I would be
highly interested in hearing from Linux experts on whether I need to
leave my machine running 24 hours a day or not.  Thanks for any
opinions.

------- Michael Winters     Peace Corps   (202)606-5543

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by Thomas Pf » Sat, 26 Feb 1994 03:50:41




>From talking with two Unix gurus I have heard conflicting viewpoints of
>whether it is dangerous to go through the Linux shutdown procedures on
>a frequent basis (i.e. daily).  I realize from reading the FAQs that there
>are utilities that you run to shut down your machine and you don't just
>shut the power down without killing processes etc...  So, I would be
>highly interested in hearing from Linux experts on whether I need to
>leave my machine running 24 hours a day or not.  Thanks for any
>opinions.

Well, this is a new thread.  Normally, people are asking if it's reliable
enough to keep running 24 hrs/day.  Now we're being asked if it's
reliable enough to shut down daily...

Any reasons why these 'gurus' think it might be dangerous to shut down
linux?  Was it linux in particular or any unix in general?

You should never turn the power off without first running the shutdown
procedures ('halt' in particular).

For the most part, I only use my home machine evenings and weekends.  It
wouldn't pay to keep it up all the time.  Therefore, it gets shut off
when I go to bed at night.  I haven't yet seen a problem from this in ~16
months of running linux.
--
tom_p                           | I could get a new lease on life

compuserve: 73303,1136          | and last month in advance.

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by Grant Edwar » Sat, 26 Feb 1994 07:43:51


: From talking with two Unix gurus I have heard conflicting viewpoints of
: whether it is dangerous to go through the Linux shutdown procedures on
: a frequent basis (i.e. daily).  I realize from reading the FAQs that there
: are utilities that you run to shut down your machine and you don't just
: shut the power down without killing processes etc...  So, I would be
: highly interested in hearing from Linux experts on whether I need to
: leave my machine running 24 hours a day or not.  Thanks for any
: opinions.

I run Linux on two machines.  One is at home and gets startup up and
shutdown almost every day.  Never had a problem.

The other machine (displayless and keyboardless) is up 24 hours a day,
7 days a week, at a remote site gathering test data and uucp-ing it
back to my Sun four times a day.  Never had a problem.

Well, there was the one time I was logged in remotely and meant to
type "fastboot" after reconfiguring some stuff, but typed "fasthalt"
instead.  It sat there halted for a couple days before I had a chance
to make the trip out to the site and hit the reset button.

As far as shutting down and starting up, I would worry about what
causes the most stress on your hardware.

--
Grant Edwards                                 |Yow!  Did I do an INCORRECT
Rosemount Inc.                                |THING??
                                              |

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by Matthew Dill » Sat, 26 Feb 1994 12:22:18



:>From talking with two Unix gurus I have heard conflicting viewpoints of
:>whether it is dangerous to go through the Linux shutdown procedures on
:>a frequent basis (i.e. daily).  I realize from reading the FAQs that there
:>are utilities that you run to shut down your machine and you don't just
:>shut the power down without killing processes etc...  So, I would be
:>highly interested in hearing from Linux experts on whether I need to
:>leave my machine running 24 hours a day or not.  Thanks for any
:>opinions.
:
:Well, this is a new thread.  Normally, people are asking if it's reliable
:enough to keep running 24 hrs/day.  Now we're being asked if it's
:reliable enough to shut down daily...
:
:Any reasons why these 'gurus' think it might be dangerous to shut down
:linux?  Was it linux in particular or any unix in general?
:
:You should never turn the power off without first running the shutdown
:procedures ('halt' in particular).
:
:For the most part, I only use my home machine evenings and weekends.  It
:wouldn't pay to keep it up all the time.  Therefore, it gets shut off
:when I go to bed at night.  I haven't yet seen a problem from this in ~16
:months of running linux.
:--
:tom_p                           | I could get a new lease on life

:compuserve: 73303,1136          | and last month in advance.

    Shutting down the machine with 'halt', assuming it doesn't give you any
    errors, is perfectly safe.

    I think some UNIX GURUs simply have an aversion to shutting machines
    down :-)

                                                -Matt

--


    1005 Apollo Way
    Incline Village, NV. 89451  ham: KC6LVW (no mail drop)
    USA                         Sandel-Avery Engineering (702)831-8000
    [always include a portion of the original email in any response!]

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by Devon Tu » Sat, 26 Feb 1994 13:26:16


Does anybody have a nice way to initiate a halt from within X safely?  Usually
I Exit Fvwm from the menu and do a halt as root.  Have any of you made a
simple fvwm menu option to do this?  It seems like doing a halt within X,
i.e. while the X and other processes are running, might cause problems, even
though halt sends all processes the warning signal, waits, sycs, then halts.

Thanks,
   Devon

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by Kevin Lent » Sun, 27 Feb 1994 14:26:50



Quote:> One reason to be wary of shutting a machine down daily is
> that there might be scripts run by cron every night at 3am
> to truncate files that would otherwise grow without bound.
> For example, my Sun searches for all .nfs* files and
> removes them.  I've also seen crontabs that truncate
> files in /var/adm nightly.  Nothing to be unduly worried
> about on a Linux machine, though.

Then just fix your rc.local so it checks the time since shutdown and
determines if it should do housekeeping.

As far as the original question goes, my machine is turned off almost every
night and these dys I am even rebooting 5 or 6 times a session because I'm
playing with SCSI code and kernel patches and a whole lot fo other reasons.
I'm yet to find a problem. It's wonderfully stable.

--
[==================================================================]
[ Kevin Lentin                   |___/~\__/~\___/~~~~\__/~\__/~\_| ]

[ Macintrash: 'Just say NO!'     |___/~\__/~\___/~~~~\____/~~\___| ]
[==================================================================]

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by Michael Winte » Sun, 27 Feb 1994 02:07:46





>>From talking with two Unix gurus I have heard conflicting viewpoints of
>>whether it is dangerous to go through the Linux shutdown procedures on
>>a frequent basis (i.e. daily).  I realize from reading the FAQs that there
>>are utilities that you run to shut down your machine and you don't just
>>shut the power down without killing processes etc...  So, I would be
>>highly interested in hearing from Linux experts on whether I need to
>>leave my machine running 24 hours a day or not.  Thanks for any
>>opinions.

>Well, this is a new thread.  Normally, people are asking if it's reliable
>enough to keep running 24 hrs/day.  Now we're being asked if it's
>reliable enough to shut down daily...

>Any reasons why these 'gurus' think it might be dangerous to shut down
>linux?  Was it linux in particular or any unix in general?

You are going to laugh, but one friend of mine, who spends much time using
linux claims his file system got roasted when he tried bringing it up after
only a couple of days shutting it down.  I am glad to say that several
people who have replied to this post say that nothing bad has happened to
them as a result of linux shutdown.  The past two days, I have shut linux
down, will no ill effects.  I just wanted to see if there was anything
unusual you have to do with linux, since I only been using it for four
days and wanted to see how "together" this beast is - it blows away most
commercial operating systems I have worked with, to say the least! :-

Quote:

>You should never turn the power off without first running the shutdown
>procedures ('halt' in particular).  

Of course.  You shouldn't do this with MAC System 7 or any operating system
for that matter.  I remember back in the "old" days, the Data General System
programmers running FIXUP to fix corrupted file links, after a power failure
occurred on a Data General MV/8000 mini-computer running AOS/VS (a definite
relative of Unix).  Here is a question to think about - Is MS-DOS / Windows
more forgiving of "accidentally" powering down without completely shutting
down, than linux?  I have a feeling it is, due to linux being a more
comprehensive operating system.

Quote:

>For the most part, I only use my home machine evenings and weekends.  It
>wouldn't pay to keep it up all the time.  Therefore, it gets shut off
>when I go to bed at night.  I haven't yet seen a problem from this in ~16
>months of running linux.
>--

Yeah - you are right - would be kind of dumb to keep on all the time for
just parttime use - the same way I use it.

- Show quoted text -

>tom_p                           | I could get a new lease on life

>compuserve: 73303,1136          | and last month in advance.

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by David F » Sun, 27 Feb 1994 04:49:47


]     Shutting down the machine with 'halt', assuming it doesn't give you any
]     errors, is perfectly safe.
]
]     I think some UNIX GURUs simply have an aversion to shutting machines
]     down :-)

One reason to be wary of shutting a machine down daily is
that there might be scripts run by cron every night at 3am
to truncate files that would otherwise grow without bound.
For example, my Sun searches for all .nfs* files and
removes them.  I've also seen crontabs that truncate
files in /var/adm nightly.  Nothing to be unduly worried
about on a Linux machine, though.
--
-david

+---------------+ David Fox
| NUKE SADDAM!! | NYU Media Research Lab
+---------------+ Courant Institute

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by Mario Cam » Wed, 02 Mar 1994 05:28:16



>Of course.  You shouldn't do this with MAC System 7 or any operating system
>for that matter.  I remember back in the "old" days, the Data General System
>programmers running FIXUP to fix corrupted file links, after a power failure
>occurred on a Data General MV/8000 mini-computer running AOS/VS (a definite
>relative of Unix).  Here is a question to think about - Is MS-DOS / Windows
>more forgiving of "accidentally" powering down without completely shutting
>down, than linux?  I have a feeling it is, due to linux being a more
>comprehensive operating system.

There are 2 reasons (AFAIK) why you need to properly shutdown a Unix
system and not an MS-DOG/WinDoze system:

1) Flushing the filesystem buffers. If you don't, you are almost
certain to lose data.

2) Properly killing processes. Since (even if you're the only user in
the machine) there are always other processes running, you need to
give them a chance to flush their data and properly shutdown.

Point (1) is pointless in MSDOG, even if you use SMARTDRV (well,
there's a SMALL probability that data will be in the cache when you
power off, but you can turn off write caching and solve the problem).
As to point (2) it might apply to WinDoze, but since there usually are
a *LOT* less apps running in WinDoze than processes in Unix that's
usually less of a problem (however, I always exit WinDoze before
powering off).

Just MHO,
--
Mario Camou / EDS Mexico Client-Server Integration Team
MS-DOS is a bug. MS-Windows is a bug with a Graphical User Interface.
------------------------------------------------------------------------------
My opinions are only mine, mine, MINE!

 
 
 

wanted - opinions on dangers of daily shutdown of Linux

Post by R.D. Auchterloun » Fri, 04 Mar 1994 00:58:58



>Does anybody have a nice way to initiate a halt from within X safely?  Usually
>I Exit Fvwm from the menu and do a halt as root.  Have any of you made a
>simple fvwm menu option to do this?  It seems like doing a halt within X,

The problem with this is that you need a setuid program to do it somewhere
unless you make shutdown/halt/reboot setuid and executable by anyone -
probably not a good idea even on a standalone/no network box.

Quote:>i.e. while the X and other processes are running, might cause problems, even
>though halt sends all processes the warning signal, waits, sycs, then halts.

That shouldn't be too much of a problem, you maybe want to give more
time in your shutdown command line so all those processes get a chance to
cleanup properly before being killed.

One problem is that your /dev/console might have been grabbed by Xconsole
which is then going to die - possibly losing some of your shutdown
messages like "you can turn of the power now...".

What I do (inspired by someone else's previously posted script) is to use
xdm, and pop-up a menu in the Xsetup0 script. I have four options - "login"
(carries on to xdm login window), "halt", "reboot" (obvious), and "console"
(kills xdm / X).  So power off is then "Exit-fvwm", wait, click on "halt",
wait, hit power switch.  This works because xdm runs this script _as root_
- so this is the only place ordinary users can shutdown from.

I'll post or mail the script if anyone wants.

-ray

 
 
 

1. 2.5.40: neofb: danger danger - Oopsen imminent

I use the neofb on my laptop, using the following audio/graphics chip:

01:00.0 VGA compatible controller: Neomagic Corporation [MagicMedia 256AV]
(rev 12) (prog-if 00 [VGA])
        Subsystem: Dell Computer Corporation: Unknown device 0088
        Flags: bus master, medium devsel, latency 32, IRQ 11
        Memory at f9000000 (32-bit, prefetchable) [size=16M]
        Memory at fdc00000 (32-bit, non-prefetchable) [size=4M]
        Memory at fdb00000 (32-bit, non-prefetchable) [size=1M]
        Capabilities: [dc] Power Management version 1

When I shut down my system, it is the last message I get. It happens after
everything has been unmounted.

After this message the system is locked solid.

DK
--
Fudd's First Law of Opposition:
        Push something hard enough and it will fall over.

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