[wplug] initrd directory

Wise, Jeremey jeremey.wise at agilysys.com
Mon May 10 14:53:13 EDT 2004


Ok. let me reiterate so as to ensure I know what was stated.

Once grub loads and calls root=/dev/sda2 (/ partition) it will look for
a directory /initrd. If this directory exists it will then look into
/boot or per /etc/fstab mount /boot volume (/dev/sda1). The kernel will
then build a ramdisk (compiled into the kernel as an option) an mount
/dev/ram0 on /initrd. This will be the mount point for the initrd to
which the kernel will call for modules of various ilk until it remounts
the file system are rw (just prior to calling runlevel start). If the
directory /initrd does not exist it assumes no initrd is required and
will try to start the runlevel based on it knowledge of / (root) and the
modules already compiled into the kernel.

Please correct if this is not how it works.

On Mon, 2004-05-10 at 14:29, Poyner, Brandon wrote:
> The man page for initrd (4) on a redhat system explains it pretty
> well.  Of course steps 1 through 6 help explain what 7 is all about.
>  
>          7. If the normal root file has directory /initrd, device
> /dev/ram0 is
>          moved  from  /  to  /initrd.  Otherwise if directory /initrd
> does not
>          exist device /dev/ram0 is unmounted.  (When moved from / to 
> /initrd,
>          /dev/ram0 is not unmounted and therefore processes can remain
> running
>          from /dev/ram0.  If directory /initrd does not exist  on 
> the  normal
>          root file-system and any processes remain running from
> /dev/ram0 when
>          /linuxrc exits, the behavior of the kernel is UNSPECIFIED.  
> See  the
>          NOTES section for the current kernel behavior.)
>         -----Original Message----- 
>         From: Wise, Jeremey [mailto:jeremey.wise at agilysys.com] 
>         Sent: Mon 5/10/2004 2:05 PM 
>         To: wplug at wplug.org 
>         Cc:
>         Subject: [wplug] initrd directory
>         
>         
>         
>         I was working on a small server that had ClarkConnect loaded.
>         It seemed
>         to be RedHat based and I was trying to clean up a bunch of
>         stuff that
>         the previos admin had left behind plus establish a mirror
>         drive.
>         
>         Long story short their was a directory /initrd off of root
>         that was
>         empty and so I thought it was not needed. I had a SuSE box to
>         compair
>         against and so I deleted it. ....Several hours later (thinking
>         it was
>         hardware or other unrealted issues) I recreated the directory
>         and it
>         booted. Once that was done I could then get back onto the
>         internet and
>         did some googling. Found that it realy should be thier on RH
>         systems.
>         Why? Why does their need to be an empty directory their for
>         the initrd
>         to load and work? My SuSE box and RH based firewall don't even
>         have
>         initird files as they are completely monolithic for all the
>         major
>         drivers (mass storage drivers).
>         
>         In need of edumakashon.
>         
>         Thanks,
>         _______________________________________________
>         wplug mailing list
>         wplug at wplug.org
>         http://www.wplug.org/mailman/listinfo/wplug
>         
>         



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