Subject: Re: how portable is ccd?
To: Ray Phillips <>
From: Paul Mather <>
List: port-alpha
Date: 05/21/2003 09:47:50
On Wed, May 21, 2003 at 10:07:02PM +1000, Ray Phillips wrote:

=> > >Where is the setup information for a ccd volume stored?  I don't mean
=> >>the configuration details in /etc/ccd.conf but what ccdconfig creates.
=> >
=> >The configuration is entirely in /etc/ccd.conf.  That's all the
=> >parameters.  :-)
=> So what exactly does ccdconfig do?  Since a ccd volume stays 
=> configured permanently after being configured by ccdconfig

It configures it until you unconfigure it via "ccdconfig -u". :-)

All ccdconfig is basically doing is setting parameters in the driver
for that CCD according to the settings in a configuration file
(default: /etc/ccd.conf).  If you look at /etc/rc.d/ccd, all it does
to start up the CCDs is a "ccdconfig -C" to process everything in
/etc/ccd.conf.  This is done at each boot, so long as you have an
/etc/ccd.conf file.

=> I thought 
=> ccdconfig would have to write something to one or more of the disks 
=> which comprise the volume, or maybe somewhere in /etc.

The configuration is in /etc/ccd.conf, by default.  If you lose this
file, you lose the ability to configure the CCD at each boot, unless
you are able to recreate it.

I have moved CCD drives from one system to another successfully.  I
currently have a CCD that I migrated that is comprised partly of RAID
volumes and partly of individual disks.  The main thing to remember
when moving them is to maintain the relative order in the
/etc/ccd.conf.  When I moved mine, I had to rename some of the drive
entries in my /etc/ccd.conf file to correspond with the logical
ordering within the CCD.

The nice thing about RAID volumes (via RAIDframe) is when you set them
to autoconfigure mode you don't have to worry about the drive IDs
changing when you add or remove drives to or from your system.  The
relative ordering information is stored in the RAID label, and so it
knows what goes where (and what is missing) when it configures a RAID
device.  (It's still handy to keep a copy of the original RAID
configuration file, as I found out when one of the drives in a RAID set
had its label become corrupted via a "hardware episode." :-) I was
able to recreate the corrupted label without losing the data on the
whole RAID 0 set.  My hat's off to Greg.)




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