Parallel Booting

[dragoran]

Colin Walters wrote:
> On Fri, 2007-07-06 at 18:17 -0400, Alan Cox wrote:
>   
>> On Fri, Jul 06, 2007 at 05:56:35PM -0400, Colin Walters wrote:
>>     
>>> Ok, I just googled and found a really good thread:
>>> http://kerneltrap.org/node/2157
>>>
>>> It's unclear to me though how much of this is actually running now.
>>>       
>> Quite a bit in terms of the disk layer. We readahead and writebehind,
>>     
>
> As I understand the readahead, it is simply requesting further blocks
> inside a single file before the read() requests come in for them. 
>
> The Hot File Clustering system on that page actually moves the files
> into a special area of the disk and and ensures they're contiguous (thus
> avoiding seeks, which plain readahead doesn't really solve).
>
> Both OS X and Windows include systems which watch the startup and
> continually optimize.  Looking at Fedora, we have the "readahead"
> package, but as far as I can tell it's static in the sense that we ship
> some definitions with the package; it's never rerun.  
>
>   
you can boot with "init=/sbin/readahead-collector"
but for me this ended up in readahead to many files... which caused a 
high diskload during boot which results into a longer boot time.