faster booting

Bill Moran wmoran at
Wed Mar 5 22:18:10 UTC 2008

In response to Daniel Feenberg <feenberg at>:
> On Wed, 5 Mar 2008, Bill Moran wrote:
> > In response to Daniel Feenberg <feenberg at>:
> >>
> >> We have several network services hosted on a FreeBSD system, and want it
> >> to come up quickly, so that these services (dhcp, nameservice, nis, tftp
> >> etc) are available when systems are restarting after a prolonged power
> >> failure.
> >>
> >> That is, several times a year we have multi-hour power failures (generally
> >> starting at midnight because that is  utility maintainance time) and our
> >> UPSs run out of power. That is OK, but we would like the systems to come
> >> up when the power returns, without going to the server room and
> >> restarting systems in a prescribed order.
> >>
> >> In most cases the clients hang because essential services are not
> >> available, and in most cases the clients do not proceed to boot later when
> >> the service does become available.
> >>
> >> So, is there advice anywhere about speeding up the boot process? It
> >> appears that most of the 1 minute 45 seconds to boot our system is wait
> >> time for checking the existence of non-existant hardware and would not be
> >> appreciable reduced with a faster CPU or disk. Are there kernel options
> >> that we could use to avoid this checking? Would recompiling the kernel in
> >> some specialized way help? Would pico-bsd be faster?
> >>
> >> About the only thing I can find is to reduce the 10 second boot screen
> >> delay - but we need to cut more than 30 seconds.
> >>
> >> The server is statically configured but the clients obtain network
> >> configuration from dhcp and pxeboot with nfs mounted root directories.
> >> Clients are FreeBSD and Linux, and we are not eager to give up pxeboot as
> >> it has greatly simplified maintainance.
> >>
> >> Any suggestions, pointers much appreciated.
> >
> > Three things I can think of:
> > * The 10 sec boot delay, which you already mentioned
> > * Make sure the wait time for SCSI devices is a low as reliably works.
> >  If it only has SCSI disks, this could probably very short, 1 sec or so
> > * Recompile your kernel removing any devices that don't exist in your
> >  hardware.
> >
> > I'm not buying this, however.  My laptop boots in ~30 seconds with a
> > mostly stock kernel.  Please provide specific details as to what's
> > slowing it down.  Are you sure it's not a slow BIOS?  Many of the Dell
> > systems we have take several minutes with BIOS self-checks before the
> > OS even starts to boot.
> The BIOS time isn't terrible - BTX shows up on the console within 15 
> seconds. The major delays happen when the last console message is about 
> atapci: (25 seconds) and ad2: (15 seconds).

Funky.  That's a Looong time to wait for an ATA controller to determine
whether or not their's a disk attached.  Do you have an ad2?  If not,
you might want to check the BIOS to see if there's an option to disable
that particular part of the ATA chain to see if that speeds FreeBSD's
probe up.

Bill Moran

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