Date: Wed, 5 Mar 2008 16:27:23 -0500 (EST) From: Daniel Feenberg <feenberg@nber.org> To: Bill Moran <wmoran@potentialtech.com> Cc: freebsd-questions@freebsd.org Subject: Re: faster booting Message-ID: <Pine.GSO.4.64.0803051623430.29394@nber5.nber.org> In-Reply-To: <20080305154351.fc53a07b.wmoran@potentialtech.com> References: <Pine.GSO.4.64.0803051450540.18940@nber5.nber.org> <20080305154351.fc53a07b.wmoran@potentialtech.com>
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On Wed, 5 Mar 2008, Bill Moran wrote: > In response to Daniel Feenberg <feenberg@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 >> 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). Daniel Feenberg > > -- > Bill Moran > http://www.potentialtech.com >
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