Re: High Availability / Replication with Sequoia

Thanks for the help guys,

I should clear up a little what I am trying to achieve I think.

The primary users of this db and application will be located in an
office, each user with a desktop machine, all networked. They need to
work with this DB in a fairly heavy kind of way, in so far as to say
that 80% of their day will be working with the application and the db.

The primary source of data will / must be located on a database server
that is actually in a different facility. It is possible to reach this
server from the office, and is done so daily, however the speed of
connection is very slow and is frequently disconnected - in short
unrelaible. To implement an extension of this 'primary' db with the
associated hardware and licensing costs at the local site is beyond
what the business is willing to pay. It also goes directly against the
'structure' that has been laid out by the IT group in that they want
all the db servers in a single location - regardless of business
impact they want to make their budget savings.

So, what I want to do is to satisfy the IT group by keeping a 'master'
copy of the db on their off-site facility, which in fact will be
populated from a source system sitting on my desk. The ETL tools will
be used for creating a completely (or as near as possible) automated
system for populating the 'master' that is offsite.

What I wanted to do next was to have Postgres installed on each of the
local users machines, along with the application they require, and run
them as a cluster - if one db goes down or one machine dies the client
software / app can still connect to the cluster and keep functioning
from another machine. I could then have the defective machine attended
to and if necessary re-built... In short the ability to work would not
be interrupted. Or at least thats the hope.

These desktops shut down each night too, as the staff leave to go
home. There is no possibility to install a server locally
(unfortunately). So with this in mind I was hoping that the
'automatic' nature of Sequoia would allow for recovery / updating from
the master or others in the cluster and keep all the local db's up to
date without the users having to do anything.

There is also a desire to have a mobile copy of this db / app for some
of the mobile users that come in to the office. They wont be able to
update while external due to the way the network is designed, but once
back in the office they could do this. I was hoping once again to keep
this as effortless as possible for the users. I am still hoping that
this may be achieveable.

In summary, what we are looking at is an install of Postgres on each
machine, a copy of Tomcat running the application, and maybe Sequoia
or Slony or some combination of both. ETL is handled separately (by
me) and the users are supposed to just be able to get on with their
work.

Do you think this is achieveable or am I up the creek and reaching too
far here?

Cheers

The Frog (you caught me out - its not my real name!)