[ZendTo] [Data migration from old installation]

[Greg Clarke]

Peter

There is an alternate method for replacing a server but it is dependent on
the old server being referenced by a CNAME.

This method gives you more flexibility in changing the server as the new
server can have a different OS e.g old Ubuntu, new RHEL, and database, old
MySQL, new SQLite.

I will use our environment as an example of how we used this method to
change both the OS, database, and upgraded ZendTo, when changing our server.

The old server had the name nickel which was referenced by the CNAME
privatebag. We advertise our ZendTo instance as Private Bag to our users as
our public mail delivery system uses Private Bags for the delivery of
secure mail. So using Private Bag allows us to piggy back on the users
existing knowledge of private correspondence.


Step 1: Change the pickup URL delivered in the pickup notices from
privatebag to nickel.

We expire pickups after 14 days so from the date of the change the system
has pickups that have either privatebag or nickel in the distributed pickup
notices. After 14 days all the pickups that were referenced by privatebag
have expired.

Step 2: Build new server called postaldistrix, install and configure
ZendTo. The pickup URL can be set to privatebag. This step can be done
during the 14 day period when privatebag pickups are expiring from the old
system.

Step 3: After all of the privatebag referenced pickups have expired from
the old system, in our case 15 days after Step 1, change the privatebag
CNAME to reference postaldistrix. Other sites can calculate when to perform
this step by using  drop-off retention period plus one.

Now the old system will have pickups referencing nickel, The new server,
postaldistrix, will have pickups referencing privatebag.

Step 4: After all of the nickel referenced pickups have expired nickel can
be decommissioned and shutdown. Finished.


The whole process is time consuming, 30 days in our case. The end result is
that we moved from CentOS 6.9 to RHEL 7.4, changed the database from MySQL
to the default database, upgraded ZendTo from 4.12 to 5.0 without any
disruption to drop off and pickup activity, or users noticing a difference
other than all the new features that became available with ZendTo 5.0.



Jules

Thanks for your work on version 5. Use of our instance has doubled in the
two months since the performing the above upgrade process and with students
now back on campus after the long summer break we are expecting use to
expand further. Feedback so far is the the new version is a lot quicker and
easier to use.


Have a good day.


Greg


SysProg, SAD, ITS
The University of Waikato
Hamilton
NEW ZEALAND
www.waikato.ac.nz
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