How do I know when a reboot is required?

[David Utidjian]

Wade Chandler wrote:
> Keith G. Robertson-Turner wrote:
> 
>> On Mon, 12 Jan 2004 23:44:16 +0000, Rui Miguel Seabra wrote:
>>
>>
>>> On Mon, 2004-01-12 at 23:36, Don wrote:
>>>
>>>> With MS Windows, it seems a reboot is required after nearly every
>>>> software update.
>>
>>
>>
>>> In principle, the only update for which a reboot is needed is Linux 
>>> (since
>>> it is the most common kernel of the GNU system), but even this may 
>>> change
>>> in the future.
>>
>>
>>
>> That would be good, it would certainly massively cut downtime on servers.
>>
>> The only way I can think of implementing this would be to perform a kind
>> of quick suspend/resume, where the "resume" remaps to a new running
>> kernel, but surely all services and current tasks would need to be
>> restarted too.
>>
>> -
>> K.
>>
>>
>>
> Remember, if you are updating packages for programs which already have 
> the .so or other file loaded, the only way to get them to start using 
> that new code is to restart them.  So, if you do a full system update, 
> it may be faster to reboot, switch run levels and back again, or create 
> scripts to restart the pieces you update often.  I usually just reboot 
> after an update.  It saves me the headache of remembering.  Unless you 
> are using an encrypted file system or some other type of password 
> protected startup you could automate this.  Though most server updates 
> aren't a good idea to automate.  You might break functionality your 
> server applications use by not reading change logs and readmes.

This functionality is partially built in with the SysV style 
initscripts. If you are on console you can simply do (as root):

telinit 1

then

telinit 3

or

telinit 5
(for a workstation).

To see which services are started and stopped at which levels do:

chkconfig --list

See man chkconfig for more details. If you prefer a more GUI method just 
run serviceconf or for a limited semi-GUI ntsysv. Another utility is 
/sbin/service. Say you load in a new apache you can simply run:

service httpd restart

To check the status of all services do:

service --status-all

It is to be noted that the "service something restart" utility sometimes 
does not actually stop and start the service but just reloads the config 
file. See man service for more details.

-David Utidjian-
Physics Lab Coordinator
Ramapo College of New Jersey