Re: Shared disk storage

Jim C. Nasby wrote:

> On Wed, Sep 07, 2005 at 12:19:19AM -0400, Tom Lane wrote:
>> Having said that, I'm not sure I believe in filesystem locks as doing
>> much to improve security in the case of multiple hosts attached to a SAN
>> filesystem. Does the locking work at all across hosts, and if it does,
>> does the lock get released reasonably promptly if the owning host
>> crashes? This seems like a there's-no-free-lunch situation.
>
> The way I see it, it will work fine for some setups, and not work for
> others. That means it won't help everyone, but it will help some. ISTM
> like it would be pretty easy to do, so why not help those who could make
> use of it?

On SUSE Linux (Tested on 10.0beta but I am fairly sure my servers running
SLES9 are the same) I have:

# ls -l /var/lib/pgsql/data/postmaster.*
-rw------- 1 postgres postgres 41 Sep 7
09:09 /var/lib/pgsql/data/postmaster.opts
-rw------- 1 postgres postgres 45 Sep 7
09:09 /var/lib/pgsql/data/postmaster.pid

Both of these files are updated when Postgres starts, with postmaster.pid
being removed when it stops, but postmaster.opts stays.

If I have a shared disk between 2 machines with Postgres running on them is
this enough to protect my data or not? Has anyone ever done anything like
this?

TIA
--

Peter Nixon
http://www.peternixon.net/
PGP Key: http://www.peternixon.net/public.asc