doing replication from two machine to one machine

[Rudy Gevaert]

Hi Patrick,

Patrick Radtke wrote:
> 
> On May 3, 2006, at 8:34 AM, Rudy Gevaert wrote:
> 
>> Hi,
>>
>> At our site I'm going to set up several cyrus servers to store all  
>> the email for staff and students.  We now have only one cyrus  server 
>> for the staff.  In the near future we are going to several  backends 
>> running cyrus for staff and students.
>>
>> I'm looking into replication.  Now I was wondering if it is  possible 
>> to replicate two (or more) cyrus servers to one replica  server?
> 
> 
> I believe so, but then what are you fail over plans?
> Are you running this in a murder?

For now we are not going to use that in a murder.  At [ 
http://users.ugent.be/~rgevaert/HA-IMAP-2.png ] you can find a picture 
of the setup we are aiming at.

Each user has his mailbox on one mailstore.  Each mailstore will be 
running an perdition imap/pop proxy that will redirect each user to the 
correct mailstore.

Each mailstore has a lun mounted from the local storage device.

I would set up repliction like this:

Mailstore 1 till 3, that are on site Rectoraat, are replicated to the 
replication server at the site S9 (replication mailstore mgr 2).

Mailstore 4 till 6, that are on site S9,  are replicated to the 
replication server at the site Rectoraat (replication mailstore mgr 1).

The replication masters are connected the same storage device as the 
local mailstores., but are on slower disks.

In this setup we always have a backup of our data at the remote site.

I have thought of the following disasters scenarios:

* a blade server fails -> a spare blade server takes over, using the storage
* blade chassis fails -> the replication mailstore mgr at the same site 
takes over for the mailstores in the failed chassis (and continues to do 
the replication for the mailstores at the other site)
* the whole site fails -> the replication mailstore mgr at the other 
site takes over with the replicated data.

What do you think of the above?

Thank you in advance,

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Rudy Gevaert                             e-mail: Rudy.Gevaert at UGent.be
Directie ICT, Afdeling Infrastructuur
Groep Systemen                                      tel: +32 9 264 4734
Universiteit Gent / Ghent University                fax: +32 9 264 4994
Krijgslaan 281, gebouw S9, 9000 Gent, Belgie               www.UGent.be
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