From: Jim C. Nasby <jnasby@pervasive.com>
To: Ketema Harris <ketema@gmail.com>
To: pgsql-performance@postgresql.org
Subject: Re: Running on an NFS Mounted Directory
Date: Thu, 27 Apr 2006 12:50:16 -0500
Message-ID: <20060427175016.GH97354@pervasive.com> (raw)
In-Reply-To: <20060427140417.GH31328@mathom.us>
References: <20060427132452.GG31328@mathom.us>
<C0764241.2CFE%ketema@gmail.com>
<20060427140417.GH31328@mathom.us>
On Thu, Apr 27, 2006 at 10:04:19AM -0400, Michael Stone wrote:
> >>redundancy, expandability
> >What I mean by these stupid flavor words is:
> >Redundancy : raid 5.
>
> You can get that without external storage.
Yes, but some dedicated storage devices actually provide good
performance with RAID5. Most simpler solutions give pretty abysmal write
performance.
> >>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.)
I'm wondering if PITR would suffice. Or maybe even Slony.
> >>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.
BTW, I know a company here in Austin that does capacity planning for
complex systems like this; contact me off-list if you're interested in
talking to them.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, ketema@gmail.com
Subject: Re: Running on an NFS Mounted Directory
In-Reply-To: <20060427175016.GH97354@pervasive.com>
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