[Beowulf] Clustering VPS servers

[Skylar Thompson]

On 3/24/2013 10:25 AM, Geoffrey Jacobs wrote:
> On 03/24/2013 01:56 AM, Jonathan Aquilina wrote:
>> What I am not understanding is the difference between using a monolithic
>> style kernel with everything compiled in vs. modules. Is there a lower
>> memory footprint if modules are used.
> Yes, if extraneous drivers are not loaded. You still need some resources
> to handle the initrd on bootup, but that shouldn't be a problem when
> everything is started.
>
> Something to read:
> http://unix.stackexchange.com/questions/65481/disadvantages-of-linux-kernel-module
>

IIRC, the initrd memory itself is freed after pivot_root (or 
switch_root) happens, so you only pay that overhead at bootup, not while 
the system is running. Of course, the initrd gives you plenty of other 
advantages besides driver flexibility. Diskless booting, for instance, 
would be much more complex without an initrd to give you a 
fully-functional (if you squint right, at least) UNIX environment before 
the main init process starts.

Skylar