[Tickets #13816] Re: read only failback for split read database

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Ticket-URL: https://bugs.horde.org/ticket/13816
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  Ticket           | 13816
  Aktualisiert Von | michael.menge at zdv.uni-tuebingen.de
  Zusammenfassung  | read only failback for split read database
  Warteschlange    | Horde Framework Packages
  Typ              | Enhancement
  Status           | Feedback
  Priorität        | 2. Medium
  Milestone        |
  Patch            |
  Zuständige       |
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michael.menge at zdv.uni-tuebingen.de (2015-01-29 15:49) hat geschrieben:

I know that horde updates some prefs like login time,
so in read-only mode there would be some functionality
los.  So we should notify the user about this, but i think the
functionality is small compared  with the possible downtime
of the whole system, unless I am missing an important feature.

Possible functionality  los:



Creating/Changing Shares ->  notify the user that the action failed
Changing Persission           ->  notify the user that the action failed
Creating/Changing Objects ->  notify the user that the action failed

updated Login Time and IP  -> Unauthorised access may not be noticed.
changes in prefs                    -> Change the setting only in the  
cache, notify the
                                                        user that the  
change is not saved.
ActiveSync/SyncML                 -> Will fail.
imp_history                              -> There will be a los of  
history for mails send,
                                                         replyed or  
forwarded, outgoing mail limitation
                                                         will not  
work, so there could be an option to
                                                        disallow sending mails

What should still work.

Read mails, create mail folders, move mails,  read access on shares  
and shared objects,


Some possible scenarios:

1. HA/LB: 2 Horde Server Active/Active and 2 databases in  
Active/Passive setup at two locations.
                   If the first location (with the active) database  
can't be reached by the second location it is
                   quit hard to automatic tell if the systems or only  
the network is down. Switching to read-only
                   on the second location would allow an admin to  
decide whats the case while his user at the
                   second location still could be used

2. Migration: Database Migration can take quite some time (Horde 3 ->  
Horde 5 more than 8h)
                  Allowing the users read only access to the old  
system, while the database is updated
                 on a new  system.