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From: Rick Gigger <rick@alpinenetworking.com>
Subject: Re: [DOCS] Online backup vs Continuous backup
Date: Wed, 4 Jan 2006 00:42:01 -0700
To: Simon Riggs <simon@2ndquadrant.com>

> I think it would all make more sense if we described the use of
> archive_command = something as being in "WAL Archive Mode". That would
> then allow us to say:
> "You can only take Online Backups while in WAL Archive Mode".
> "If you ever wish to perform PITR, you must use WAL Archive Mode".
> "If you backed-up in WAL Archive Mode, you can perform an Archive
> Recovery".

It seems to me there are two different context in which one would be  
making statements like this.  And what we are "allowed to say"  
depends greatly on context. These contexts are as follows:

1) Explaining the feature set of postgres to a potential user.
2) Explaining to an actual postgres user how to actually do something.

In the first case it makes the most sense to me to use industry  
standard or very intuitive terminology to the extend that it exists.   
ie (Transaction Logs vs. WAL).  Incremental Backup and Point in Time  
Recovery seem to be fairly commonly used and understood database  
buzzwords for someone to investigate the feature set of an RDBMS.

In the second case it seems to me that the most important thing is  
that you pick terminology that is consistent, unambiguous and clearly  
defined.  Log archival, PITR, etc are not point and click operations  
like they are in say MS SQL Server.  This gives us more flexibility  
but it also requires a deeper understanding.  If someone is unwilling  
or unable to to learn whatever terminology you happen to come up with  
then it seems to me they shouldn't even be attempting to set up one  
of those features.  At the same time if the terminology you uses  
changes all the time (is not consistent), or if you can't figure out  
what any of the terms mean (they are not clearly defined) or if you  
use terms like "online backup" to mean both types of backup but then  
use it once in a specific circumstance where only one usage is  
appropriate (you are using the terms ambiguously) then users will be  
confused and it will be your fault not theirs.

Just my 2 cents

Rick Gigger