Author: Ian Southam Date: To: robert rotman CC: exim-users Subject: Re: [Exim] database lookups & cdbs
On Thu, Feb 10, 2000 at 02:44:36PM +0100 robert rotman wrote :
> if this happens to a mailserver tons of mails are bounced...
> the database lookups works well on my place and i _NEED_ the flexibility
> of the database. > IMHO, if you build cdb from a database you do not really need a databes!
Not at all, your central database is where all the data is stored, that way
you have one point of update and eliminate the need for any data redundancy or
occasions were the same data must be entered several times. All the other
points of contact for the database source their data from that one point.What
you eliminate is the reliance on one database to source your data in real time.
If you produce local copies or mirrors of the original database which can run
independently of the main database that is fine, it still protects you against
one outage in your system becoming a nightmare. The point is, your worse case
scenario becomes out of date data rather than no data. In such situations
where out of date information is unsuitable or dangerous, then, you have no
choice but to access your database(s) in real time.
Ultimately though, however you do it, whether by scripting, mirroring or
otherwise you do need to ensure the integrity of the data used by the end
applications - such as your radius server ;-).
There is no point IMHO of building resiliant distributed solutions and then
making the whole thing hinge on one piece of the jigsaw.
