[Samba] Re: PDC, BDCs - how do you synchronize roaming profiles?

[Tomasz Chmielewski]

John H Terpstra wrote:

>>I thought of this approach:
>>
>>- keep profile size to the minimum (20-30 megs),
> 
> 
> How will you control the size of the profile? I can not see a practical 
> solution to do this.

Didn't think of it yet.

Several years ago, in a rather big university facility I saw something
like that on Windows NT workstations: if student profile was too big,
user was disallowed to logout until he/she deleted some data (there was
a pop-up window "your profile is bigger than XY megabytes, you can't log
out, delete some files etc.").
The only way to logout was to delete some files and try again, or to
poweroff the machine (which meant the profile was lost).

Anyone knows what this could be?


>>- rsync changes of the profile to the other domain controllers when user
>>logs out.
> 
> 
> The trouble is that you have to do it from each WAN location and there is just 
> no way to maintain data integrity with multiple source locations and multiple 
> targets.

Given the fact that one user can log in only once and in one place, I
think it is doable: just rsync changes to other places using "postexec"
%U script. There are some problems to be solved (what if changes can't
be uploaded for some time and we have two different profiles?), but I
think I have to live with that as I didn't think of anything better so far.


It would be great if there was some "profile-daemon" which could take 
care of profile replication:

1) user logs out and uploads profile to a local Samba server,

2) "profile-daemon" notices that user logged out and finished uploading 
profile locally,

3) "profile-daemon" attempts to copy profile to other location(s); if 
upload successful, exit

4) if upload unsuccessful, retries,

5) if user wants to log in locally again - no problem; if user is a 
olympic sprinter and managed to reach another building before the 
profile was fully uploaded, he should be notified during login that 
profile is not in sync (and ask what to do),

6) if upload unsuccessful because link broken, triggers dial-up and 
notifies other locations that the profile is *not uploaded*,

7) now other locations know that profiles are not in sync, and won't 
allow user to log in (or allow to log in, but warn that profile is not 
in sync),

8) every 5 or 10 minutes "profile-daemons" should communicate and 
exchange information; if they can't communicate, they know it, and 
during login present a user a window explaining "last profile change was 
on Friday, 11:34 etc., what to do"...


This would need some additional software installed on a Windows side, 
too I think.


Anyway I think it could be a killer Samba feature, especially for bigger 
organizations like universities.



>>Do you think it's a good approach, or should I think of something else?
> 
> 
> I'd suggest local profiles for such mobile users. Remember you can use Windows 
> XP Pro off-line folders to replicate data to a home server.

But these mobile users can sit in front of a random workstation, so I
can't do it like that.


Tomek