Here are some ideas I put down that might be of use.
#--
# $Id: arabeyes-move,v 1.1 2003/12/18 06:30:13 elzubeir Exp $
# Arabeyes.org - Moving from razi to sina
#--
It is impossible to achieve a total of 0 downtime for all the services
offered by Arabeyes.org. This is not because of the technical complexities
of the move but rather due to the delay which will be caused by DNS
propagation.
For this reason, we must be selective about what gets moved first.
I. Prepare sina
- setup mysql (and import latest mysql db from razi) [this process will be
done a few times again, but the import is just a one line thing]
- setup postfix with the same configuration used on razi
- setup apache (with php4 and mysql support)
- setup MoinMoin (wiki)
- install bugzilla
- install docbook tools for SGML processing
- install Python
- dictdb (and supporting utilities)
II. Moving things on the peripheral
We can start with the things that are not tied with other parts of Arabeyes.
Namely, wiki, bugzilla, qamoose and dict. Those should be setup first. They
are not dependent on other parts of Arabeyes and are not very heavily used.
They should be moved and setup on sina first. Then, DNS entries should point
to sina instead of razi for their domains. What is running on razi should
continue to be up for a few days (possibly until the move is over just to
be sure).
III. Moving the essentials
1. Mail
MX records in the DNS records allow one to setup backup mail exchange servers.
razi's IP has been added as a backup in case of razi going down. This sets
the stage for a clean move from razi without the users experiencing any
mail downtime.
When we are ready to move the mail, we will simply shut down postfix on
razi and remove the MX record pointing to it. Mail will try to connect to razi
and when it fails will hit sina. When DNS propagates it will simply go directly
to sina.
2. Web
Leave the website running on razi for 3 days post the move. In the meantime,
move the site along with the MySQL db and get it to work on sina. Both should
continue to be mirrors of one another, while the DNS records propagate.
3. CVS
Moving the CVS would be the last step. Once the CVS is copied over the pserver
is setup, update the DNS records and shut down the pserver on razi. This
will be the only service which will experience downtime. Unfortunately there
is no other graceful way of going about it -- as we cannot afford to have
conflicting commits.
Of course one can leave both running on sina and razi and update the CVS
repository manually if commits are made, but it is not worh the hassle.
EOF
Did I miss anything?
Regards
--
-------------------------------------------------------
| Mohammed Elzubeir | Visit us at: |
| | http://www.arabeyes.org/ |
| Arabeyes Project | Homepage: |
| Unix the 'right' way | http://elzubeir.fakkir.net/ |
-------------------------------------------------------
Attachment:
pgp00007.pgp
Description: PGP signature