Re: Standby servers and incrementally updated backups

On Jun 29, 2007, at 10:15 AM, Jim Nasby wrote:

> On Jun 25, 2007, at 4:54 PM, Erik Jones wrote:
>> On Jun 25, 2007, at 4:40 PM, Simon Riggs wrote:
>>> On Mon, 2007-06-25 at 16:00 -0500, Erik Jones wrote:
>>>> On Jun 25, 2007, at 3:40 PM, Simon Riggs wrote:
>>>>>> If I'm correct, then for large databases wherein it can
>>>>>> take hours to take a base backup, is there anything to be
>>>>>> gained by
>>>>>> using incrementally updated backups?
>>>>>
>>>>> If you are certain there are parts of the database not touched
>>>>> at all
>>>>> between backups. The only real way to be sure is to take file
>>>>> level
>>>>> checksums, or you can trust file dates. Many backup solutions
>>>>> can do
>>>>> this for you.
>>>>
>>>> Wait, um, what? I'm still not clear on why you would want to run a
>>>> backup of an already caught up standby server.
>>>
>>> Sorry, misread your question.
>>>
>>> While you are running a warm standby config, you will still want
>>> to take
>>> regular backups for recoverability and DR. These are additional
>>> backups,
>>> i.e they are not required to maintain the warm standby.
>>>
>>> You can backup the Primary, or you can backup the Standby, so most
>>> people will choose to backup the Standby to reduce the overhead
>>> on the
>>> Primary.
>>
>> Ok, yeah, that's what I was thinking and is where we are headed in
>> the next month or so here at work: we already have a standby
>> running and will be adding a second standby server that we will be
>> using for snapshot backups (packaged with the pertinent wal
>> files...) as well as periodically bringing the second standby up
>> to run dumps from just to cover all of our bases and also to be
>> able to take our main primary server down for maintenance and
>> still have both a production and standby running. I guess I was
>> really just wanting to make sure I wasn't missing some other big
>> usage for incremental backups from the standby.
>
> Note that (currently) once you bring a standby up you can't go back
> to standby mode without restoring the filesystem level backup you
> started with and replaying everything.

Right, got that.

Erik Jones

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