Speedying up the boot for Fedora

[Jean-Eric Cuendet]

Hi,
To speed the boot of Fedora, the taken approach is to readahead the
files needed by the daemons/tools run during boot. This approach works
well but the actual approach is to pre-load some files from a static
defined file. (This is accomplished by /etc/init.d/readahead which reads
  files from /etc/readahead.files)

There is IMHO at least 2 problems:
- When the boot process change, either by removing/adding services, the
fiels that must be readahead change. But the readahead.files don't.
- The readahead process don't read the files in the best order to
minimize the head movement on the hard disk
- The readahead process don't rearrange the files on disk so the
readahead process can be quicker.

Why not implement a dynamic mechanism to know which files need to be
read in readahead?
- End of kernel init
- Register a (KProbes or LSM?) hook that listen to which files are read
- Boot the system
- End of system boot, read the files that were read during boot itself.
- Update the readahead.files file so the readahead could be quicker.

A second step could be to rearrange the files so the readahead could
read them without too much head movemement on the HD. Perhaps with help
of e2fsdefrag?

Do you have any comment?
-jec

-- 
Jean-Eric Cuendet
Riskpro Technologies SA
Av du 14 avril 1b, 1020 Renens Switzerland
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E-mail: jean-eric.cuendet at rptec.ch
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