Gregory Symons posted <[EMAIL PROTECTED]>, excerpted
below,  on Thu, 14 Apr 2005 10:10:49 -0400:

> I think it doesn't handle parallel booting very well... the progress bar
> sometimes goes backwards

Parallel booting may or may not work.  I get the feeling from the comments
I've seen that they only put it in because people wanted it, but it
complicates things enough, and for little enough gain*, that the only
support you may get for a parallel boot issue is instructions for turning
the option back off.

It worked here for quite awhile, then quit, with network services.  Seems
the newer network script returns "up" for the dependencies before it
actually /is/ up, so all the associated networking daemons start.  For
stuff like privoxy and bind, that works fine -- they could actually start
independent of network except there'd be little use for them, at least
since I only access them thru loopback anyway, so that's all they have to
listen to, but ntp-client doesn't work so well when the net's down, since
it needs it immediately, which means ntpd won't work as well either, since
it may have a quite a way to skew, when the net /does/ come up and it can
connect, which will of course do "interesting" things to its drift
calculations.  Anyway, I had to turn parallel startup back off, to get
things to work right again.

*Parallel startup seldom gains all /that/ much anyway, because only
certain things are dependency free enough to do so, and what's gained by
the parallel init is often almost lost due to the attempt to disk seek
multiple items, often relatively far apart on the disk, at once.  Of
course, this doesn't necessarily apply for those with good, high-speed
RAID arrays, particularly if they are multi-processor (or multi-core)
as well. 

Anyway, the largest time taker here is the on-boot quick-fsck, which is
early enough in the boot process nearly everything else depends on it, so
it can't be paralleled.  Even if it could, again, the bottleneck is the
disk access so throwing additional disk access in to load something else
isn't going to help.

So... the option is there for those that want to play with it, but it's
not enabled by default because the benefits are normally quite low, and
the potential complications rather high.  As such, it's not surprising to
me at all that the progress bar has a few bugs in it, when used in that
mode.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman in
http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html


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