From: John Wiencek <jwiencek3@comcast.net>
To: Jan Peters <haseningo@gmx.de>
Cc: Ganesh Korde <ganeshakorde@gmail.com>
Cc: Pepe TD Vo <pepevo@yahoo.com>
Cc: Pgsql-admin <pgsql-admin@lists.postgresql.org>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>
Subject: Re: PostgreSQL replication failover
Date: Thu, 14 Jan 2021 09:03:38 -0600
Message-ID: <C134F9AD-B771-4A3A-B9A2-7F4D0777FF26@comcast.net> (raw)
In-Reply-To: <trinity-4813039b-0953-4d98-a901-cc0a6807c285-1610612162770@3c-app-gmx-bap12>
References: <trinity-64a56362-8af1-4ec9-b408-d4256ce65fd2-1610526479876@3c-app-gmx-bs17>
<976875a5adf1c1cda0d55e6da0313f30dc8059f6.camel@cybertec.at>
<526397214.877472.1610544243527@mail.yahoo.com>
<CAPNyb0UMysUm2KzYoy==HtNXbq2LjJanxTzxBRJjdPXt4W418A@mail.gmail.com>
<trinity-4813039b-0953-4d98-a901-cc0a6807c285-1610612162770@3c-app-gmx-bap12>
Hi
You can use repmgr, which is free, or EFM which requires a subscription.
John
> On Jan 14, 2021, at 2:16 AM, Jan Peters <haseningo@gmx.de> wrote:
>
> Hello,
>
> thank you very much for the answers.
> Can you tell me some tools, but they must be available for s390 ZLinux.
> For our purposes in redhat linux
>
>
> Gesendet: Mittwoch, 13. Januar 2021 um 19:46 Uhr
> Von: "Ganesh Korde" <ganeshakorde@gmail.com>
> An: "Pepe TD Vo" <pepevo@yahoo.com>
> Cc: "Jan Peters" <haseningo@gmx.de>, pgsql-admin@lists.postgresql.org, "Laurenz Albe" <laurenz.albe@cybertec.at>
> Betreff: Re: PostgreSQL replication failover
>
> You can use different tools which detects if primary fails and automatically promotes standby.
>
> To assure all data on standby you should use synchronous replication.
>
> On Wed, 13 Jan 2021, 6:54 pm Pepe TD Vo, <pepevo@yahoo.com[mailto:pepevo@yahoo.com]> wrote:
>
>>> If you shut down the primary server cleanly, all changes will be replicated,so you should be good.
>
>>> During a failover, that is, if the primary suddenly fails, there is always
> the possibility that you lose some transactions, unless you use synchronous
> you said above which I don't need to run promote to make it failover as long as I set synchronous on? The last couple of weeks I have a failure on the primary server and can't run on a slave. It picks up as reading mode only.
>
>
> Bach-Nga
>
> No one in this world is pure and perfect. If you avoid people for their mistakes you will be alone. So judge less, love, and forgive more.
> To call him a dog hardly seems to do him justice though in as much as he had four legs, a tail, and barked, I admit he was, to all outward appearances. But to those who knew him well, he was a perfect gentleman (Hermione Gingold)
> **Live simply **Love generously **Care deeply **Speak kindly.
> *** Genuinely rich *** Faithful talent *** Sharing success
>
>
>
>
>
> On Wednesday, January 13, 2021, 06:25:53 AM EST, Laurenz Albe <laurenz.albe@cybertec.at[mailto:laurenz.albe@cybertec.at]> wrote:
>
>
>
> On Wed, 2021-01-13 at 09:27 +0100, Jan Peters wrote:
>> we are running postgresqlserver on s390 zLinux machines. The distribution
>> is RedHat 7 and RedHat 8, so we do not have the many x86 tools available.
>>
>> We always run 2 instances with a replication (streaming) async mode, the replica
>> is in hot_standby and we use it for read-only accesses. About the setup we have the following question:
>>
>> How is an orderly failover accomplished? Our current procedure is.
>>
>> 1. primary stop
>> 2. promote replica to primary
>> 3. create standby.signal on old primary
>> 4. change primary_conninfo on old primary
>> 5. start old primary as new replica
>>
>> Is this processing correct? Are there any other steps that simplify a failover?
>> How can we be sure that all changes have been transferred from the old master to the replica?
>
> What you describe is not a failover, but a switchover.
>
> If you shut down the primary server cleanly, all changes will be replicated,
> so you should be good.
>
> During a failover, that is, if the primary suddenly fails, there is always
> the possibility that you lose some transactions, unless you use synchronous
> replication.
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com[https://www.cybertec-postgresql.com]
>
>
>
>
>
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To: pgsql-admin@postgresql.org
Cc: jwiencek3@comcast.net, haseningo@gmx.de, ganeshakorde@gmail.com, pepevo@yahoo.com, pgsql-admin@lists.postgresql.org, laurenz.albe@cybertec.at
Subject: Re: PostgreSQL replication failover
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