Date: Thu, 11 Sep 1997 19:27:40 -0500 (CDT) From: "Jay D. Nelson" <jdn@qiv.com> To: Steven Ames <steve@news.cioe.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Clustering/fail-over capability? Message-ID: <Pine.BSF.3.96.970911190022.509A-100000@acp.qiv.com> In-Reply-To: <199709111913.OAA07761@news.cioe.com>
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On Thu, 11 Sep 1997, Steven Ames wrote:
>
> > Mirroring disks is pretty easy to do, the built-in disk striping driver
> > (ccd) does this already. But the rest is pretty tricky.
>
> But in this case you'd really want to be mirroring the disks across servers,
> not within the same server. ccd can't do that.
No -- you don't want to mirror between servers. Put _two_ differential
controllers in both machines and _two_ external SCSI towers cabeled
between the two machines. Mirror disks on one controller to the
disks on the other controller.
The takeover is reasonably complicated -- managing machine and process
state as well as outstanding locks and terminal sessions is
non-trivial in an exclusive takeover situation. Concurrent access to
shared disks, which you would need for load balancing is even worse.
I think this is way beyond the scope of reasonable expectations for a
volunteer effort. While many have the skills -- and maybe the desire
-- groceries are more important.
Commercial software that does this goes for $10-30K. Maybe you could
hone your skills (and future income) and implement this for us?
-- Jay
>
> I believe that 'clustering' is going to become a more important topic in
> the near future. Having fail over and load balanced servers is desired for
> larger 'mission critical' applications.
>
>
> -Steve
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