[CentOS] when to reboot after updates

Warren Young warren at etr-usa.com
Thu Apr 9 14:30:00 UTC 2009

nate wrote:
> Jerry Geis wrote:
>> What is the rule of thumb for reboots after updates...
> only with new kernels. 

...and then only when you want what the new kernel provides.

I have my systems configured so yum is allowed to download and install 
new kernels, but don't usually reboot unless I want the specific thing 
the new kernel fixed, or have to reboot for some other reason.  This 
saves me some hassle in rebuilding third-party drivers.

Windows boxes have to reboot on almost every upgrade because the file 
I/O semantics don't allow replacing files that are in use, except in 
some very limited cases.  Windows has a feature that *ix type boxes 
don't need, which is that a program can schedule a file to be replaced 
on the next reboot.  It's part of the "move file" API.  Installers do 
this when they try to replace a file and fail, which is why an installer 
might not always prompt for a reboot on completion; it depends on 
whether the program was running when you ran the installer.  This is 
also why so many Windows installers demand that you shut everything else 
down while you install the program.  They're trying to help you out.

I bring this seemingly off-topic thing up here because it's why a lot of 
people get the idea that upgrades mean reboots.  It simply isn't usually 
needed in the *ix world.  It's why my uptime records for *ix boxes are 
over a year, while my Windows boxes rarely stay up for a full month and 
almost never beyond that due to Patch Tuesday.

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