[OpenAFS] mount points and replication problems
Tue, 12 Jul 2005 15:00:19 +0200
On Tue, Jul 12, 2005 at 01:17:05PM +0200, C?dric CACHAT wrote:
> this is the first time I write and I am pretty new to AFS. I have a
> question regarding mount points in AFS.
> Here is what I'm trying to achieve:
> I want all my users to have their home directory in AFS, the plan is to
> set an AFS tree looking like:
> I created the following volumes on my primary server:
> and then I mounted them using the fs command :
> *# fs mkm /afs/cell/usr common.usr* and so on... (I didnt use *# fs mkm
> /afs/_._cell/usr common.usr *maybe my problem comes from here?)
> So far everything is under control.
Did you explicitely mount the RW-instance of the homedirectory-volumes?
-> fs mkm /afs/cell/usr/homes/user1 user.user1 -rw
Otherwise you would have RW-acces to the homdirs only if there are
> Since I have many sites, I have set up one AFS server on each site.
> Because all users don't work on the same site I decided to create user.*
> volumes on their closest server, so I created volume user.user1 on the
> primary server and user.user2 on the secondary server.
> Without any replication it works perfectly if BOTH servers are running.
> If one is down, say the master, then acces to a user's home-dir is
> Thats's were it's getting complicated for me: I then set up replication
> to the second site so that I have:
> primary server secondary server
> root.afs (RW) root.afs (RO)
> root.cell (RW) root.cell (RO)
> common.usr (RW) common.usr (RO)
> common.homes (RW) common.homes (RO)
> user.user1 (RW) user.user1 (RO)
> user.user2 (RO)
> user.user2 (RW)
You most probably want to have RO-copies of "structural volumes" like
root.afs, root.cell, common.usr, common.homes on both fileservers.
> Looking at the array above, if the primary server is down, user1 should
> be able to access is home dir but Read Only whereas user2 should be able
> to read/write to his home directory.
No. user.user2 resides on primary-server so user2 will have no access at all.
> That's exactly what I want.
> The problem is user2 can only read and not write (il I try ls
See '-rw' -option of 'fs mkm'.
> /afs/.cell, it hangs then says timeout). Is it normal or did I miss a thing?
> Second question, I don't know what to set their homedirectory to (read
> from LDAP at login), do I have to use /afs/_cell_/usr/homes/user1 or
The first. There should be no "dot-path-component" in a user's homedir as long
as you mount the homedir-volume '-rw'.
> If I use the former, when both servers are running they can't write to
> their directory, they have to cd to /afs/.cell/usr/homes/user1 in order
> to write which is not practical; if I use the latter, it works all right
> when both servers are running but when the primary is down, it fails to
> acces the home directory (server timeout, the branch /afs/.cell is down).
That's expected behaviour because root.cell(RW) (aka. /afs/.cell) resides
> Did someone ever try to set up such a network, or is it impossible?
Impossible is to automagically switch a user's homedir to RO when there's
no RW-volume available. That's because the '-rw'-switch forces the AFS-client
to mount the RW-volume - *without* any fallback to RO.
> Could you tell me then how should I mount my tree?
|- cell root.cell
| `- home homes
| `- user1 user.user1(-rw)
|- .cell root.cell(-rw)
> I think my problems come from the .cell and cell, I don't quite
> understand the impact it has on the rest of the tree.
Whenever you want to i.e. add a user, just access /afs/.cell/home,
add the mountpoint and 'vos release' the homes-volume.
All volumes along the path (root.afs, root.cell, homes) should have
RO-instances on both fileservers.
Your users needn't access .-paths.