Kernel Startup Delay

Kernel Startup Delay

[Mark Cuss]

Hello!

I am setting up a server with 4 SCSI hard disks, two of which I will jumper
to have a delayed spin up as to not bake the power supply.  These two drives
will contain a striping RAID.  I am concerned that the kernel will load off
of the other drives and attempt to start this RAID before the disks have
even spun up - is there a way to have the kernel delay its startup for a
certain number of seconds while all the drives spin up?

Any hints are greatly appreciated.

Mark

Re: Kernel Startup Delay

[Alan Cox]

> to have a delayed spin up as to not bake the power supply.  These two drives
> will contain a striping RAID.  I am concerned that the kernel will load off
> of the other drives and attempt to start this RAID before the disks have
> even spun up - is there a way to have the kernel delay its startup for a
> certain number of seconds while all the drives spin up?

The kernel scsi code issues test-unit-ready commands and will (should 8)) do
the right things and wait for the drives to spin up. 

Alan

Re: Kernel Startup Delay

[Ignacio Vazquez-Abrams]

On Tue, 21 Aug 2001, Mark Cuss wrote:

> Hello!
>
> I am setting up a server with 4 SCSI hard disks, two of which I will jumper
> to have a delayed spin up as to not bake the power supply.  These two drives
> will contain a striping RAID.  I am concerned that the kernel will load off
> of the other drives and attempt to start this RAID before the disks have
> even spun up - is there a way to have the kernel delay its startup for a
> certain number of seconds while all the drives spin up?
>
> Any hints are greatly appreciated.
>
> Mark

I thought that this was a function of the SCSI BIOS? I know that with the
Adaptec AHA-x940xx and AIC-78x0 you can tell the card/chip to spin up the
drives after individually-configurable delays, and then continue booting the
system once all the drives have spun up. Does your card/chip have a similar
feature?

-- 
Ignacio Vazquez-Abrams  <ignacio@openservices.net>

Re: Kernel Startup Delay

[Colonel]

In clouddancer.list.kernel, you wrote:
>
>Hello!
>
>I am setting up a server with 4 SCSI hard disks, two of which I will jumper
>to have a delayed spin up as to not bake the power supply.  These two drives
>will contain a striping RAID.  I am concerned that the kernel will load off
>of the other drives and attempt to start this RAID before the disks have
>even spun up - is there a way to have the kernel delay its startup for a
>certain number of seconds while all the drives spin up?
>
>Any hints are greatly appreciated.


You will find that the BIOS will wait for the drive spin up.  I use 9
drives and power 'on' takes a few minutes.  Additionally, the control
electronics is active on the drives, which would delay any attempt to
start RAID.



-- 
Windows 2001: "I'm sorry Dave ...  I'm afraid I can't do that."

Re: Kernel Startup Delay

[Jim Roland]

I'm sure others have contributed to this, but depending on how much delay
you're talking about, you may be able to set a startup delay via your SCSI
BIOS (reference the settings screen showing all SCSI IDs and settings for
each) if you have an Adaptec AHA2940, I know you can do this.  Others you
may need to taste before adding seasoning.

If you don't want to, or are unable to adjust the SCSI Controller's BIOS,
you can insert a startup delay if you're using LILO, and have it wait "x"
seconds which you can adjust in tenths of seconds (50=5 seconds) and have
LILO wait before starting the kernel enough time for your drives to startup.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jim Roland, RHCE (RedHat Certified Engineer)
Owner, Roland Internet Services
     "The four surefire rules for success:  Show up, Pay attention, Ask
questions, Don't quit."
        --Rob Gilbert, PH.D.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

----- Original Message -----
From: "Mark Cuss" <mcuss@cdlsystems.com>
To: <linux-kernel@vger.kernel.org>
Sent: Tuesday, August 21, 2001 11:11 AM
Subject: Kernel Startup Delay


> Hello!
>
> I am setting up a server with 4 SCSI hard disks, two of which I will
jumper
> to have a delayed spin up as to not bake the power supply.  These two
drives
> will contain a striping RAID.  I am concerned that the kernel will load
off
> of the other drives and attempt to start this RAID before the disks have
> even spun up - is there a way to have the kernel delay its startup for a
> certain number of seconds while all the drives spin up?
>
> Any hints are greatly appreciated.
>
> Mark
>
>
>
> -
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