[kdepim-users] Re: Akonadi + nfs home directories

[Martin (KDE)]

Am Freitag, 8. April 2011 schrieb Lars Behrens:
> Am 05.04.2011 10:28, schrieb Martin (KDE):
> >>> rm -r ~/.local/share/akonadi
> >>> mkdir -p /tmp/akonadi-USERNAME/akonadi
> >>> cd ~/.local/share
> >>> ln -s /tmp/akonadi-USERNAME/akonadi .
> >>> 
> >>> Then edit $HOME/.config/akonadi/akonadiserverrc and add
> >>> 
> >>> [Connection]
> >>> SocketDirectory=/tmp/akonadi-USERNAME/
> 
> [...]
> 
> > This has to be done per script. This should not be that hard to
> > implement. Add this script to /etc/kde/env (on fedora - on suse
> > this path may be different) it takes car of the correct
> > settings. But don't use /tmp for this. These data may be deleted
> > automatically or at every reboot. Use /var/tmp.
> 
> Ok, found time to test it on two clients, seems to work. Thank you
> Myrosia and Martin (btw. the path in SUSE is /usr/share/kde4/env/).
> 
> To work means: I can start kdepim/kaddressbook with akonadi in
> several clients, but of course new records only show up on the
> client on wich they have been created.
> 
> But it is a workaround which might give us time to search for a
> solution in the long run.
> 
> > Adding the UNIX_SOCKET line at every config setup may be a bug.
> > Is this overwritten if you set this socket to /var/tmp/akonadi-
> > USERNAME/mysql.socket?
> 
> Hasn't happened here yet.
> 
> > But why don't you want to sync the home directory from/to the
> > server at login/logout? May be Microsoft is not the reference
> > here, but they do it since the beginning (at least can do).

I have the same ammount of data in my home drive (about 1 GByte). The 
initial sync takes several minutes but most of the data does not 
change during the sessions. And rsync takes care syncing only changed 
data.

rsync does not take care of data altered on the server in the mean 
time. So if user A logs in on client X and after that on client Y both 
get the same basic configuration. If user A logs out from client Y all 
changes data are synced back to the server. If user A logs in on 
client Z he/she will get the config data from Y-logout. If user A logs 
out from client A only those data will be synced which are newer. So 
maybe user A looses some settings made on client X but later made on 
Client Y in a different way.

I once tried this with unison, but had minor problems with conflicts. 
unison can do a two way sync, but to me this seems not to be 
necessary.

> 
> Main reasons: Too much data per user to shovel around (up to GB per
> user/session ). Same problem here like with nfs, how to deal with
> two running seasons.

Currently last change wins. I don't know of any other way to implement 
this. And I don't know how windows handles this. With text files an 
intelligent kind of merge may be possible but this will not work with 
binary data. And automatic conflict handling will be very poor.

At least I don't have the problem with concurrent access of binary 
data at the same time.

And currently I have implemented this for kde logon/logoff only and 
for notebooks only.

Just a brief description on my sync process: My user authenticate 
against kerberos. With the kerberos ticket the rsync authenticates 
against the ssh server on file server side (rsync via ssh) and 
automatically sync remote against local at login (and vice versa at 
logout). This takes a few seconds (depending on file count and size).

> 
> > And terminals don't get around the problem. If a user is logged
> > in twice the programs will run twice as well. Only if the user
> > gets two different views of the same desktop this will work. But
> > I don't know of any system implementing this.
> 
> I am hoping to find out a way to take over exising sessions, like
> the way it happens with windows server when you log on.

I tried freeNX which is similar to RDP from windows. You can close a 
running session and continue (reopen the session) later on. There are 
some minor problems with font size and repaint but it seems to work 
fine. But I have not tested this for a longer time so my experience is 
limited.

Martin

> 
> Cheerz,
> Lars
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