From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tom Korach <tom@safekeep.com>
cc: pgsql-admin@lists.postgresql.org
Subject: Re: Is file system replication sufficient to recovery?
In-reply-to: 
 <CALQRbyyfjY7=z6Z8EGWj0aqPX0_Uk95v6pQkGoHbCDW=srFOGw@mail.gmail.com>
References: 
 <CALQRbyyOqWPNBMmeHEa1T2NKqWHaUvjw7uyqR_vp9syVrD3UeA@mail.gmail.com>
 <2276564.1640884845@sss.pgh.pa.us>
 <CALQRbyyfjY7=z6Z8EGWj0aqPX0_Uk95v6pQkGoHbCDW=srFOGw@mail.gmail.com>
Comments: In-reply-to Tom Korach <tom@safekeep.com>
	message dated "Thu, 30 Dec 2021 12:43:04 -0500"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <2286513.1640886731.1@sss.pgh.pa.us>
Date: Thu, 30 Dec 2021 12:52:11 -0500
Message-ID: <2286514.1640886731@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/2286514.1640886731%40sss.pgh.pa.us>
Precedence: bulk

Tom Korach <tom@safekeep.com> writes:
>> What do you mean exactly by "file-system replication"?

> RAID1 setup (specifically, between two disks or EBS volumes [on AWS]),
> using LVM.

Maybe I'm missing something, but AFAIK plain old RAID will not protect
you against any scenario except failure of a single disk.  It certainly
won't do anything to help you revert to a prior database state.

The docs page I pointed you to is part of a chapter that lays out all
the backup methods the PG community considers reliable.  I strongly
suggest sticking to one of those and not trying to take shortcuts.
(The following chapter on high-availability setups is relevant
reading as well.)

			regards, tom lane