adventures in booting

[Kyrre Ness Sjobak]

tor, 02.12.2004 kl. 18.59 skrev Colin Walters:
> On Thu, 2004-12-02 at 12:40 -0500, David Zeuthen wrote:
> 
> > I'm almost positive it requires kernel changes to do this the right way;
> > one naive idea is to have a userspace daemon, capturing what blocks are
> > read when (kernel tells this daemon using the kernel events layer). This
> > would run in the first three minutes on each and every boot. When the
> > system is idle (and only when running on AC power!) another daemon
> > rearranges blocks on the disk. What blocks to rearrange could be the
> > result of a computation involving several three-minute result sets.
> 
> Rearranging sounds complex and dangerous, since it requires deep
> integration with the filesystem.  The online resizing took quite a long
> time to appear and that is conceptually much simpler.  Why not do it on
> the block device layer (without knowledge of the filesystem) and just
> copy those blocks to a reserved area of the block device?  Disks are
> big, duplicating say 100MB for this purpose wouldn't be bad.  We would
> need to ensure that mkfs.ext3 would leave enough space for this though
> (and probably whatever does the copying would have to make sure that the
> filesystem wasn't in the way; perhaps an ext flag).
> 

Hmm... /boot is usually quite "overbig", and must be situated within a
booting (ie. not at the end) part of the disk...