From: Simon Riggs <simon@2ndquadrant.com>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Cc: PostgreSQL-documentation <pgsql-docs@postgresql.org>
Subject: Re: [HACKERS] Online backup vs Continuous backup
Date: Fri, 30 Dec 2005 13:35:37 +0000
Message-ID: <1135949737.5052.21.camel@localhost.localdomain> (raw)
In-Reply-To: <200512261846.jBQIkcN12733@candle.pha.pa.us>
References: <200512261846.jBQIkcN12733@candle.pha.pa.us>
On Mon, 2005-12-26 at 13:46 -0500, Bruce Momjian wrote:
> Tom Lane wrote:
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > > I suggest the following patch to rename our capability "Continuous
> > > Backup".
> >
> > This doesn't seem like an improvement. "Online backup" is the standard
> > terminology AFAIK.
>
> But why is it the standard terminology? It doesn't seem logical.
Well, as Greg says its a physical backup that can be done on-line, so
online backup makes perfect sense to me. I've never had somebody say
"that makes no sense" before. Nomenclature is different everywhere, I
accept.
I generally describe it like this:
Logical Backup
- use pg_dump - must be done on-line
Physical Backup
All file copy only
- must be Cold/Off-line backup
All file copy + WAL archiving
- allows Hot/Online or Cold/Offline backup
People understand those terms...
When do I mention PITR? Well, I describe this as Archive Recovery, with
an option to go to end-of-logs, or to a point-in-time.
[In the code, the mode variable is InArchiveRecovery.]
I do think that saying "do you use PITR?" makes little sense. We should
be talking about the backup mode, not the potential future recovery
mode.
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".
Best Regards, Simon Riggs
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Cc: simon@2ndquadrant.com, pgman@candle.pha.pa.us, tgl@sss.pgh.pa.us, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] Online backup vs Continuous backup
In-Reply-To: <1135949737.5052.21.camel@localhost.localdomain>
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