Date: Thu, 27 Apr 2006 10:04:19 -0400
From: Michael Stone <mstone+postgres@mathom.us>
Subject: Re: Running on an NFS Mounted Directory
In-reply-to: <C0764241.2CFE%ketema@gmail.com>
To: Ketema Harris <ketema@gmail.com>
Cc: pgsql-performance@postgresql.org
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	pgsql-performance@postgresql.org
Message-id: <20060427140417.GH31328@mathom.us>
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 <C0764241.2CFE%ketema@gmail.com>
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On Thu, Apr 27, 2006 at 09:41:21AM -0400, Ketema Harris wrote:
>>No, backups are completely unrelated to your storage type; you need them
>> either way.
>Please another post. I meant the storage would do the back ups.

Which isn't a backup. Even expensive storage arrays can break or burn 
down.

>>redundancy, expandability
>What I mean by these stupid flavor words is:
>Redundancy : raid 5.

You can get that without external storage.

>Expandability : the ability to stick another drive in my array and get more
>storage and not have to turn of the db.

You can also get that without external storage assuming you choose a 
platform with a volume manager.

>>Do you 
>> need the ability to do snapshots?
>Yes.

If that's a hard requirement you'll have to eat the cost & performance 
problems of an external solution or choose a platform that will let you 
do that with direct-attach storage. (Something with a volume manager.)

>>Do you want to share one big, expensive, reliable unit between
>> multiple systems? Will you be doing failover?
>Yes, and Yes.  Really on one other system, a phone system, but it is the
>crux of my business and will be writing a lot of recorded phone calls. I am
>working with a storage company now to set up the failover, I want the db and
>phone systems to never no if the storage switched over.

If you actually have a couple of systems you're trying to fail over, a 
FC SAN may be a reasonable solution. Depending on your reliability 
requirement you can have multiple interfaces & FC switches to get 
redundant paths and a much higher level of storage reliability than you 
could get with direct attach storage. OTOH, if the DB server itself 
breaks you're still out of luck. :) You might compare that sort of 
solution with a solution that has redundant servers and implements the 
failover in software instead of hardware.

Mike Stone