Making a dynamically-linked root

[Andrew Gallatin]

Gordon Tetlow writes:
 > 
 > There will be a performance hit associated with this. I did a quick
 > measurement at boot and my boot time (from invocation of /etc/rc to
 > the login prompt) went from 12 seconds with a static root to 15
 > seconds with a dynamic root. I have yet to perform a worldstone on
 > it.

Wow!  That's a 25% pessimization.  I'm afraid that other heavily
scripted and or fork intensive environments may fair just as poorly
(dynamic web content, SMTP servers, etc) as the startup scripts.

I don't want to sound harsh, and I do appreciate your work.  However,
I think the last thing FreeBSD needs now is to get slower.  We're
already far slower than that other free OS.  Shouldn't we consider
making the dynamic root optional and leaving a static root as
standard?

 > The reason to do this is two-fold. One is to give better support
 > for PAM and NSS in the base system. The second is to save some disk

Are better support for these features worth the 25% performance penalty
you mention above?

 > space. Currently (on my x86 box), /bin and /sbin are 32 MB. With
 > a dynamically linked root (and some pruning of some binaries), the
 > /bin, /lib, and /sbin come out to 6.1 MB. This should be great for
 > people with 2.x and 3.x era root partitions that are only about 50
 > MB.

Assuming disks cost $1.00 US per gig, this 25% performance penalty
saves roughly 2.5 cents worth of disk space.  Admittedly, embedded
environments need the disk savings and might not care about the
performance penalty.  But that's just another argument for making it
optional.


Drew