Does a kernel assisted file system reorder make sense?

Christian Volkmann
2009-11-15T10:39:55Z

Hi,

I just have read some articles about faster booting systems
(Ubuntu 9.10) , SSD, hard disks, latency and seek times...

Due to this I have some ideas which I like to discuss.
I am for sure not the first with this idea, but I do not
find any discussion about it. :)

Shouldn't it be possible for the kernel to provide an ordered
loaded block list read from disk ? This could be used for a kind
of "forced reorder" for a file system tool.

May be this would also fasten the system start from a hard disk.
I could imagine a scenario like:
- kernel start (boot loader )
- kernel to keep a list of the read blocks (on a per filesystem base)
- kernel to log this list just before init starts.
- on demand: kernel to continue the recording
- on demand: kernel can signaled to log this list.
(e.g. graphic log in ready )

This logged list could be use from a new tool like "e2reorder"
for ext2/3/4 to reorder the blocks within the file system(s) to
reduce the seek delay for a start from a hard disk.

The logged list could also be used as a "to load/cache first" list
for the kernel/initrd boot. This might fasten the start without
special file system tools or for file systems without support.

But this would only make sense if a system boot is delayed by
hard disk seek times. I have no SSD to check if a SSD boots
faster. Does anyone have the experience if a SSD boots faster?

Best regards,

Christian