[OpenAFS] Volume numbers

Jeffrey Hutzelman jhutz@cmu.edu
Wed, 06 Dec 2006 19:10:50 -0500

On Monday, December 04, 2006 03:31:07 PM +0100 Hartmut Reuter 
<reuter@rzg.mpg.de> wrote:

> Jakub Witkowski wrote:
>> Hello!
>>> From my observation of AFS volume ID numbers, it appears that they are
>> always large, pseudo-random numbers unique to a given cell. I'd like to
>> ask if there any lower/upper bounds to that value? Does volume number
>> zero can exist? Or is that perhaps a special case?
> The volume numbers in a new cell start with what the vldb database
> initialization has but in as starting number. This is 0x20000000
> or decimal 536870912.

There are some very old cells with lower volume ID's.  The lowest volume ID 
in use in my cell is 1.  However, most cells will not have volume ID's less 
than 0x20000000, and there can never be a volume with ID 0.  The starting 
value was chosen to insure that when those very old cells switched to using 
the VLDB, there would be no possibility of the vlserver allocating a volume 
ID that had already been used.

-- Jeffrey T. Hutzelman (N3NHS) <jhutz+@cmu.edu>
   Sr. Research Systems Programmer
   School of Computer Science - Research Computing Facility
   Carnegie Mellon University - Pittsburgh, PA