Re: faster boots?

From: Eric W. Biederman (ebiederm@xmission.com)
Date: Fri Apr 05 2002 - 01:14:12 EST


Alan Cox <alan@lxorguk.ukuu.org.uk> writes:

> > I find that on heavily scsi systems: one machine spins each of 13 disks
> > up sequentially. This makes the initial boot take 3-5 minutes before
> > init even gets its foot in the door. If someone made a patch to spin
> > up scsi disks on the first access, I'd gladly give it a test. ;-)
>
> Ditto. Especially if it spun them down again when idle for a while.
>
> The scsi layer does several things serially it could parallelise. It isnt
> just disk spin up its also things like initialising all scsi controllers
> in parallel.

I'm interested in this kind of thing too. Though I am wondering if the IDE
layer has the same kind of issues. I notice because the kernel initialization
time is 50% of my boot time. I have the kernel loaded 3 seconds from
power on...

My impression is that the time during kernel initialization is either
spent spinning up disks or in a million device probes and things going
on behind the scenes. I haven't had a chance to look farther though.

Eric
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