RedHat Cluster Suite and Piranha

Hi all,

I'm trying to set up an IP load balancer using the RedHat Cluster
Suite software and RedHat Enterprise Linux. I've got four identical
Dell servers I'm working with (test system), two will be the load
balancers (active and backup) and two will be the backend server farm.
My questions is this, is it possible to set this system up using only
one machine to be the load balancer? The Cluster Suite documentation
makes it look like you HAVE to have a backup machine for the load
balancer, is this true or not? Anyone have any suggestions or ideas
about that, I'd be glad to hear them.

Thanks in advance,
Doug Farrell

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Doug Farrell <(E-Mail Removed)> wrote:
> Hi all,

> I'm trying to set up an IP load balancer using the RedHat Cluster
> Suite software and RedHat Enterprise Linux. I've got four identical
> Dell servers I'm working with (test system), two will be the load
> balancers (active and backup) and two will be the backend server farm.
> My questions is this, is it possible to set this system up using only
> one machine to be the load balancer? The Cluster Suite documentation

What sense makes your cluster, if you still have a single point
of failure?

--
Michael Heiming (GPG-Key ID: 0xEDD27B94)

Remove +SIGNS and www. if you expect an answer, sorry for
inconvenience, but I get tons of spam.
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> > I'm trying to set up an IP load balancer using the RedHat Cluster
> > Suite software and RedHat Enterprise Linux. I've got four identical
> > Dell servers I'm working with (test system), two will be the load
> > balancers (active and backup) and two will be the backend server farm.
> > My questions is this, is it possible to set this system up using only
> > one machine to be the load balancer? The Cluster Suite documentation
>
> What sense makes your cluster, if you still have a single point
> of failure?

Capacity?

It's a lot cheaper to dish out large quanitites of web content (and some
other services) with small clustered machines than to use one large
machine, and using a load balancer will give you a bit better control than
round-robbin DNS will, and not everyone needs "five-nines".

steve

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Steve Wolfe <(E-Mail Removed)> wrote:
> > > I'm trying to set up an IP load balancer using the RedHat Cluster
> > > Suite software and RedHat Enterprise Linux. I've got four identical
> > > Dell servers I'm working with (test system), two will be the load
> > > balancers (active and backup) and two will be the backend server farm.
> > > My questions is this, is it possible to set this system up using only
> > > one machine to be the load balancer? The Cluster Suite documentation
> >
> > What sense makes your cluster, if you still have a single point
> > of failure?

> Capacity?

> It's a lot cheaper to dish out large quanitites of web content (and some
> other services) with small clustered machines than to use one large
> machine, and using a load balancer will give you a bit better control than
> round-robbin DNS will, and not everyone needs "five-nines".

You have ever run a larger site (>10^6 hits/24h)? You know how
much traffic Linux/apache can handle easily on a reasonable box?

BTW
Linuxvirtualserver doesn't need an external load balancer it's
built in.

--
Michael Heiming - RHCE (GPG-Key ID: 0xEDD27B94)

Remove +SIGNS and www. if you expect an answer, sorry for
inconvenience, but I get tons of spam.
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> > It's a lot cheaper to dish out large quanitites of web content (and
some
> > other services) with small clustered machines than to use one large
> > machine, and using a load balancer will give you a bit better control
than
> > round-robbin DNS will, and not everyone needs "five-nines".
>
> You have ever run a larger site (>10^6 hits/24h)? You know how
> much traffic Linux/apache can handle easily on a reasonable box?

Less than 10^6 hits/day, but not *much* less.

Yes, of course I know how much Linux/Apache can handle on a reasonable
box. However, have you ever run a larger site, where content generation
involves manipulating data from lots of different sources?

If it were nothing but a bandwidth matter, Google could probably make do
with a handful of dual-Xeons.

> BTW
> Linuxvirtualserver doesn't need an external load balancer it's
> built in.

Yes, it's built in, but it's fairly traditional to have one machine acting
as the load balancer (or "director"), and others serving web content. LVS
does let you have a local server, but it's not exactly the optimal for
regular operation.

steve

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Steve Wolfe <(E-Mail Removed)> wrote:
[..]

> Yes, of course I know how much Linux/Apache can handle on a reasonable
> box. However, have you ever run a larger site, where content generation
> involves manipulating data from lots of different sources?

Yep, I think so. From experience, crappy written SQL, does suck
the hell out of a db server, no matter how larger the system is.
There's often much room for improvements which doesn't cost extra
money, but is easily ignored. Throwing hw on the problem is not
uncommon.

> If it were nothing but a bandwidth matter, Google could probably make do
> with a handful of dual-Xeons.

Ack.

> > BTW
> > Linuxvirtualserver doesn't need an external load balancer it's
> > built in.

> Yes, it's built in, but it's fairly traditional to have one machine acting
> as the load balancer (or "director"), and others serving web content. LVS
> does let you have a local server, but it's not exactly the optimal for
> regular operation.

Just a hint for the OP that he doesn't really need one.
During the time of kernel 2.2.x, did run a LVS cluster it worked
very well, only some minor problem while syncing the static
content. Today one could use GFS or alike for shared storage
between members. Sure a load-balancer has pros, but the OP didn't
sound as he would really need one.

--
Michael Heiming - RHCE (GPG-Key ID: 0xEDD27B94)

Remove +SIGNS and www. if you expect an answer, sorry for
inconvenience, but I get tons of spam.
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Hi everyone, OP here,

Thank you all for your comments, though no one really answered my
original question about whether or not the RedHat Cluster Suite IP
Load balancer could be setup to use one machine rather than two.

I agree with an early comment that having one load balancer creates a
single point of failure, but our system already has a mirror system so
that's less of an issue. The problem I'm trying to solve is server
load. Right now if one of our mirror sites goes down, the other site
can't handle all the load. Each site consists of one server that hosts
one of our products. So what I'm trying to do is add capacity within
the mirror site. Once I have the load balancer in place (at both sites
eventually), I can add additional back-end servers as the need arises.

Anyway, thanks for your responses,
Doug Farrell

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Doug Farrell <(E-Mail Removed)> wrote:
> Hi everyone, OP here,

> Thank you all for your comments, though no one really answered my
> original question about whether or not the RedHat Cluster Suite IP
> Load balancer could be setup to use one machine rather than two.

You got some support with Redhat Enterprise Linux, I'd simply ask
RH.

[..]

--
Michael Heiming (GPG-Key ID: 0xEDD27B94)

Remove +SIGNS and www. if you expect an answer, sorry for
inconvenience, but I get tons of spam.
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