May you please share what types of check if there to
guarantee the backup is trustworthy.
Regards,
Dinesh Chandra
|Database administrator (Oracle/PostgreSQL)| Cyient Ltd. Noida.
From: ldh@xxxxxxxxxxxxxxxxxx [mailto:ldh@xxxxxxxxxxxxxxxxxx]
Sent: 02 March, 2017 9:57 PM
To: Rick Otten <rottenwindfish@xxxxxxxxx>; Dinesh Chandra 12108 <Dinesh.Chandra@xxxxxxxxxx>
Cc: pgsql-performance@xxxxxxxxxxxxxx
Subject: Re: How Can I check PostgreSQL backup is successfully or not ?
It'd be so nice to have some checks to guarantee the backup is trustworthy. Restoring the db is imho not a very good option in general:
- large databases are a problem. My db is about 3TB. Time plus disk space is a big blocker.
- also, what if the backup is incomplete? Just restoring the db successfully is not enough right? You'd have to compare with the prod to make sure nothing
was missed... in a fast moving outfit where the db today will have tons of new/changed deleted stuff from yesterday.. how to even do that?
I am in a warehouse environment, so I have given up on guaranteeing backups and in a case of trouble, i'll spend 20h rebuilding my db. So I have a way
out but i'd much prefer working with trustworthy backups.
Sent from my BlackBerry 10 smartphone.
Sent:
Thursday, March 2, 2017 08:19
Subject:
Re: How Can I check PostgreSQL backup is successfully or not ?
|
This reminds me - I have had a case where the exit code for pg_dump was successful, but the backup was still corrupted on disk. By all means check the exit code, but I strong encourage a second validation, such as the index listing, to
increase your confidence that the backup was successful.
The best way to ensure good backups is to establish a regular practice of restoring a backup to another database. The easiest such practice to justify and implement is to maintain a developer/development database, and to use your production
database backups to rebuild it on a regular basis. Other approaches could include regularly scheduled Disaster Recovery exercises, or simply spinning up throw away cloud instances for the purpose.
pg_dump uses the ordinary postgresql COPY command to extract data from the tables. Beyond that, I'm not sure how it works. Sorry I can't help you there.
On Thu, Mar 2, 2017 at 7:05 AM, Dinesh Chandra 12108 <Dinesh.Chandra@xxxxxxxxxx> wrote:
Hi,
When I issue the bleow command
> ./bin >pg_dump -U dummy_user dummy_database; echo $?
I checked with Linux TOP command on the same server, it was showing COPY database.
What exactly it doing ??
Regards,
Dinesh Chandra
-----Original Message-----
From: vinny [mailto:vinny@xxxxxxxxx]
Sent: 27 February, 2017 7:31 PM
To: John Gorman <jgorman@xxxxxxxxxxxx>
Cc: Rick Otten <rottenwindfish@xxxxxxxxx>; Dinesh Chandra 12108 <Dinesh.Chandra@xxxxxxxxxx>;
pgsql-performance@xxxxxxxxxxxxxx;
pgsql-performance-owner@xxxxxxxxxxxxxx
Subject: Re: [PERFORM] How Can I check PostgreSQL backup is successfully or not ?
On 2017-02-27 14:29, John Gorman wrote:
> Even though it's not listed in any of the documentation or “pg_dump
> --help” you can check the return code of the process. A return code
> greater than 0 (zero) usually indicates a failure
>
> ./bin >pg_dump -U dummy_user dummy_database; echo $?
>
> 1
>
> FROM: pgsql-performance-owner@xxxxxxxxxxxxxx
> [mailto:pgsql-performance-owner@xxxxxxxxxxxxxx] ON BEHALF OF Rick
> Otten
> SENT: Monday, February 27, 2017 3:36 AM
> TO: Dinesh Chandra 12108
> CC: pgsql-performance@xxxxxxxxxxxxxx
> SUBJECT: Re: How Can I check PostgreSQL backup is
> successfully or not ?
>
> Although it doesn't really tell if the pg_dump was successful (you'll
> need to do a full restore to be sure), I generate an archive list. If
> that fails, the backup clearly wasn't successful, and if it succeeds,
> odds are pretty good that it worked:
>
> On Mon, Feb 27, 2017 at 4:35 AM, Dinesh Chandra 12108
> <Dinesh.Chandra@xxxxxxxxxx> wrote:
>
> Hi,
>
> We are taking daily full backup of PostgreSQL database using PG_DUMP
> which is automatic scheduled through Cronjobs.
>
> How can I check my yesterday backup is successfully or not?
>
> Is there any query or view by which I can check it?
>
> REGARDS,
>
> DINESH CHANDRA
>
> |DATABASE ADMINISTRATOR (ORACLE/POSTGRESQL)| CYIENT LTD. NOIDA.
It's important to note the distinction between
"the backup process did not fail"
and
"we now have a trustworthy backup"
And you can go full-paranoia and say that you can successfully create a perfectly working backup of the wrong database.
So what is it that you want to make sure of:
1. Did the process give an error?
2. Did the process create a usable backup?
What are the chances of #1 reporting success but still producing a bad backup?
And can #2 fail on a good database, and if so, can you detect that?
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