[PC-BSD Dev] Wild idea to speed up boot process

Luca Ferrari fluca1978 at infinito.it
Sat Aug 10 02:21:03 PDT 2013


On Fri, Aug 9, 2013 at 8:00 PM, Claudio L. <claudio at hpgcc3.org> wrote:

> Once it's in RAM, any file that exists in this ram disk would be used
> instead of the underlying root file system.
>
> On system shutdown, or actually as soon as boot process is finished, this
> ramdisk can be dumped back to disk, to preserve any changes.
>
> All we would need is some hook to detect which files are read during boot,
> and copy them to the ram disk on the fly if they are not already there.


Uhm...sounds to me like a duplicate of the vnode cache layer: each
time access to a file is detected you have to map it to the ramdisk,
and then the system maps it into the vnode cache. I don't know if this
will produce a real gain considering the complexity it adds.
Something that could work better, in my opinion, is an autonomous
system able to "adjust" a ramdisk each time the system powers off so
that the next time it boots the ramdisk would be still valid
considering any changes the user has done in the system itself (e.g.,
configuration files).

Luca


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