Re: Hot standby from Debian to Windows

Hi!

>Since you are moving between different OSes you will need to use some form
>of logical replication as binary replication will not work.

I can use Hyper-V or something other to run Debian with Windows.

This hopefully will also allow to bypass Windows 20 connection limit so that
more than 20 users can connect.

>Given that you are Postgres 12 you could use the builtin logical
>replication:
>https://www.postgresql.org/docs/12/logical-replication.html

I see possibilities:

1. Use Hyper-V to run Debian container and Postgres binary replication
2. Use Hyper-V to run Debian container and Postgres logical replication
3. Use Windows and Postgres logical replication.
4. Use Hyper-V to run Debian container and backup utility for whole disk
block level backup

>How that needs to managed is going to need more information. As a start:
>1) Downtime allowed?

Yes. If main server stops, I can tell users to enter backup server address
instead of main server.

>2) All databases to be replicated or just some?

I can create separate cluster so that all databases and users will be
replicated.
There are 30 databases with total size 70 GB. Size will increase slowly
every day when new data is entered.
There are some test and demo databases whose replcation is not really
required but those can also replicated if this

>3) Permissible lag between servers?

Currently backups are created every night and restored in new server.
Backup of 67GB data takes 1 hour, transfer 1 hour, restore and analyze to
new server 4 hours. Total 6 hours. So current lag in 6 .. 24 hours.

Goal is to decrease this lag.

>4) How are you going to deal with the down server and how do you plan on
>bringing it up again?

VPS hosting company will bring it up again. I will then manually synchronize
two clusters when users continue to enter data, this is not time critical.

Andrus.