[ubuntu-users] Double Trouble with GRUB

[Andrew Farris]

On Mon, 2009-08-31 at 14:54 -0600, Ted Hilts wrote:
[enormous snip]
> 
> This next part may not be relevant but here goes anyway.  I usually have 
> no problem if the booting up occurs after there has been a shut down for 
> a while like an hour or more. If I try to boot up right after the 
> problem has occurred then chances are it won't boot properly and most of 
> the file system will be missing.  There are a total of 8 drives one of 
> which is the DVD/CD rw and the rest are hard drives with most of them 
> NTFS formatted but one is "ext3" and a partiion in another is also 
> "ext3" for "/".  The power supply was sized for all these drives.  In 
> addition, the system is dual boot, Ubuntu and XP.  This probably means 
> that there is a large capacitance that would hold power maybe enough 
> power so that the charge does not melt off for a while.  This is bad 
> power design and could cause a problem when turning on the machine. Or, 
> maybe the power design is good but the component that should drain 
> residual power has failed -- still a bad design.

This information is actually extremely helpful and is, in my opinion,
quite relevant.  Having such a large number of drives, and having
strange problems after doing cold boots screams PSU issue to me. If you
could please:

     1. What kind of PSU do you have? (make/model/Watts)
     2. What other hardware do you have installed in your PC aside from
        the drives (i.e. stuff in the expansion slots... extra sound
        card/graphics card etc.)?
     3. What processor do you have(make/model)?
     4. How much RAM are you using?

It's entirely possible that your PSU could be powerful enough to run all
the drives once they're up, but afaik hard drives draw the largest
ammount of energy when they are spinning up.  I've certainly seen
problems before where a large number of disks was causing prower
issues... although those problems manifested as crashes during 3D apps.

Also be sure to take into account the fact that your PSU isn't 100%
efficient... 80% is pushing it (only if you get an 80+ certified drive),
and 50-60% is usually safe, and allows for some breathing room.

If you are fully confident that the PSU should be able to handle all
that hardware, you could also check your BIOS for settings related to
bootstepping (I think that's what it's called). Basically what this is
supposed to do is allow you to delay the power-up/spin-up of some of
your disks, so you can power them up slowly, or one/two at a time,
rather than throwing that huge load on the PSU all at once.

hope that helps.


-- 
Andrew
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