faster booting

[Daniel Feenberg]

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.

Daniel Feenberg
NBER