[OpenAFS] Re: bos blockscanner

Hartmut Reuter reuter@rzg.mpg.de
Sat, 26 Jan 2013 10:50:41 +0100

When OpenAFS started in 2000 I pushed a lot of extensions into it to make it
easier to maintain MR-AFS. I think at that time we already were the last site to
use it. The next years the source code of MR-AFS could be reduced to the very
specific parts on the server side while with these extensions for all other
subdirectories simply the openafs code could be used.

The scanner was a stand alone program which traversed the volume metadata to
find out which files needed to get a copy elsewhere and which files were
eligible for wiping (removing from disk). In extreme situations it could be
helpful to stop the scanner...

There are many other remains of MR-AFS in different source files of openafs
which savely could be removed now that MR-AFS is out of service since five years.

MR-AFS was shutdown finally in 2008. Since than we are running AFS/OSD which has
a all the features MR-AFS had and some more. I am working on the project to
bring the AFS/OSD change into the official openafs source code.


Andrew Deason wrote:
> On Fri, 25 Jan 2013 19:50:41 +0100 (CET)
> Thorsten Alteholz <openafs@alteholz.de> wrote:
>> the command 'bos help' says something about 'blockscanner' and
>> 'unblockscanner'.  This shall start something like
>> '/usr/afs/bin/scanner -block'. But I did not find anything about such
>> scanner. Can anybody please shed some light on this? Is this a new
>> fearture for the future?
> No, it is very old. I believe that is there to accommodate installations
> with MR-AFS. MR-AFS is for using AFS with HSM systems but is not freely
> available or open source or anything; you can google around for what
> little information exists about it. I'm not sure if it's still in use.
> Those rpcs hard code the commands they run, ugh...
> I don't have any familiarity with it, but from what I've seen in the
> OpenAFS source, I think the 'scanner' process is something that shuffled
> data between disk and tape. Normally it runs continuously or something,
> but those commands allow you to temporarily disable or enable
> migrations.

Hartmut Reuter                  e-mail 		reuter@rzg.mpg.de
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