Re: pg_basebackup for streaming base backups

On Fri, Jan 21, 2011 at 07:02, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> On Fri, Jan 21, 2011 at 1:00 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Fujii Masao <masao(dot)fujii(at)gmail(dot)com> writes:
>>> On Thu, Jan 20, 2011 at 10:53 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> In the case you sketch, there would be nothing to stop the (non root)
>> postgres user from renaming $PGDATA/mnt to something else and then
>> inserting his own trojan-horse directories.
>
> Hmm.. can non-root postgres user really rename the root-owned directory
> while it's being mounted?

No, but you can rename the parent directory of it, and then create
another directory inside it with the same name as the root owned
directory had.

>> Moreover, I see no positive *good* reason to do it.  There isn't
>> anyplace under $PGDATA that users should be randomly creating
>> directories, much less mount points.
>
> When taking a base backup, you don't need to take a backup of tablespaces
> separately from that of $PGDATA. You have only to take a backup of $PGDATA.

But why are you creating tablespaces in the first place, if you're
sticking them in $PGDATA?

I'd put myself in the +1 camp for "throw an error when someone tries
to create a tablespace inside $PGDATA".

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/