[OpenAFS] Move a IP from CellServer?

[Horst Birthelmer]

On Nov 12, 2004, at 11:37 AM, Lars Schimmer wrote:

> Yeah, replicate is easy, but mounting a new volume doesn't work.
> Example: volume subversion with submounts a b c d ...
> So the submounts are mounted RW, but the subversion volume seems to be 
> RO.
> Even on BOTH database servers and every fileserver we've got. Why, I 
> don't know,
> but with only the RO copy of the subversion volume, I can't mount 
> another volume
> under ../subversion/t or else. Even fs rmmount subversion doesn't work.
> fs: You can not change a backup or readonly volume Is the error to be 
> faced with.
> And I can't understnad why the first database server with the original 
> Root.cell
> (which was mounted RW) puts out this message, to.
>

No, the database server doesn't matter. If you work with the RO copy 
you cannot change it. That's the way it is ;-) (That's why it's called 
RO ...)
I think your problem is a misunderstanding of the concept. You cannot 
balance between the RW copy and the RO but between the ROs.
If you mount the volume RW you will loose contact when your server goes 
down (the RW is unique). If you want replication you can do that but 
only with read only data.

The root.cell isn't on your database server. (It might be the same 
machine) It has nothing to do with what database server is serving you.

> |> Point 2: We thought the 2nd server to takeover the management if the
> |> first gone
> |> down. But while a reboot of the first (main) server, our cell hung 
> and
> |> no client
> |> worked well. Is this a kind of wrong thinking of us? Or a failure of
> |> OpenAFS
> |>
> |
> | If you have just two of 'em that's also pretty much normal behavior. 
> If
> | you reboot the sync site you'll have some "out" time (timeouts) until
> | the client notices that the server isn't there. It should actually 
> work
> | afterwards.
> | If you reboot the server with your root.afs and/or your root.cell 
> that's
> | also normal.
>
> Oh, with 3 database Servers it runs better?
> And why shouldn't I mount the root.cell RW on the other Database 
> servers?
> At least, how can I remount the root.cell IF it is already mounted?

I'm heavily under the impression we're talking about different mounts 
here.
You can mount any volume at any point in AFS at any time (if you're 
allowed to) and in any mode even if that's not the same volume from the 
same server (RO/RW).

> ~From our point of view OpenAFS is a filesystem distributed on our PCs 
> at work.
> And we need nearly all volumes to be RW for most people 
> (home-directory,
> work-directorys, CVS, FTP,....) So for us the RO replicas are mostly 
> only for
> backup. It would be nice if the OpenAFS Client could read the Data 
> from the RO
> copies, write to the RW and sync them after writing. But that's heavy 
> work &
> load ;-)

That's pretty useless.
You're keeping too much data on too much servers. That's what backups 
are for ... or RAIDs or whatever but not AFS.
Why would you want to create an inconsistency?? (and really knowing 
better) We have "sync on close" on files on the RW so what keeps your 
client from _reading_ that data?? (Maybe it's a "cool" concept ;-) )

> In our view the only sense for RO copies to be public are archives 
> like CDs or
> other static data, but these are big data and easily and fast 
> recoverable, so
> why RO backups...?
>

RO copies are read only and can be kept on more than one server because 
they are read only and there is no need for consistency checks.


Horst