Re: Database migration across different operating systems

On 8/1/19 11:01 π.μ., Stéphane KANSCHINE wrote:
> Hey !
>
> Le lun.  7 janv., vers 22:51, Natalie Wenz exprimait :
>> We are in an unusual circumstance, where we need to move all of our
>> Postgres 10 databases from their homes on servers running FreeBSD 11
>> with ZFS to servers in another data center running Red Hat Linux 7.6
>> (also with ZFS), with minimal downtime.
>>
>> I understand that the recommended, safest, approach would be to
>> dump/restore. We intend to do that wherever possible.
> It's not anymore since PostgreSQL have logical replication. You can
> initialize you FreeBSD cluster with a pg_basebackup and you follow
> updates with logical streaming.

Hmm, maybe you mean pg_dump --schema-only? I cannot see how taking physical copy with pg_basebackup will help with
logicalreplication. Logical replication has its own initial snapshot phase. Doing a 
 
pg_basebackup would work if followed by truncating all tables, but that's duplicate work and equivalent to pg_dumpall
--schema-only| psql -f -
 

>
>> However, we have some databases that require high
>> availability/minimal downtime that are also very large. (50 TB, for
>> example)
> With logical replication, is it's permanently up to date in
> miliseconds, you can switch when you want.
>
>> If it helps: The cpu architecture is the same on both hosts, and
>> we’ll be running Postgres with the same version and same build
>> options.
> Your OS or cpu architecture doesn't matter, really :-)
>
> Regards,


-- 
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt