wmoran at potentialtech.com
Wed Mar 5 20:44:50 UTC 2008
In response to Daniel Feenberg <feenberg at nber.org>:
> 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
> 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
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.
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