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On Thu, 21 Jun 2007, Rio wrote:
> We presently want to test a clustering system using one of our active servers
> and a mirror that is identical in every way. All machines are AMD64 opteron
> arch running Gentoo.
>
> Here is our setup and what we hope to do:
>
> One of our production servers is a linux-vserver host that runs 57 virtual
> servers within, and uses 4 public networks assigned to it and the various
> guest servers for a total unique ip count of 247 across the 4 networks.
I see Malcolm has beat me to it.
you have two identical realservers, each of which presents a
bunch of services on a bunch of IPs (247) on bunch (4) of
physical networks.
> some virtual servers are busy. We have several websites using in excess of
> 70GB/mo each with one website using an average of 173GB/mo in bandwidth. The
> mail server processes as high as 1/2 million msgs /hr with an average of
> 260,000/hr.
the smtp is OK as long as it's an MTA. If the mail is being
delivered locally, you'll have to handle the many reader
single writer problem.
> What I wish to do is have some kind of control box (or multiple if needed)
director.
You'll need two if you want failover.
> to
> manage which of the real servers will act on a request.
to route packets to the realservers.
> We would have, to
> allow for additional machine expansion, 4 private /24 networks asssigned to
> each host server and guests (total 8 pvtnets) to represent the 4 public
> networks.
LVS can handle any number of networks. The number of
networks is controlled by Linux not LVS.
> This control box(s) will have to accept the public ip request and map it to
> one of a list of private ip addresses servicing that particular public ip
> address/port combination. It could be 'round robin' or 'least used' no matter
> we just want all servers to actively participate rather than have one sitting
> idle waiting for the fateful day it will be needed. Fail-over is required so
> if a machine dies or otherwise is unavailable, the control box(s) will use
> the active machines automatically.
you install failover as a separate layer above LVS.
Ldirectord or keepalived are two ways of doing this.
> for best bandwidth allocation we would use 5 nics in the control box, one
> public and one for each of the private networks (or less if it is deemed
> overkill) and each real server would have the same number of pvtnet nics for
> its services.
use whatever number of NICs makes your life easy.
> we use iproute2 exclusively with 2.6.20 kernels. We upgrade kernels regularly
> for security/bug fixes once they have proven themselves, so I guess we update
> once or twice a year.
I never update a tested and working machine. You're
asking for trouble. I had the same version of ntpd (from the
libc4 days) running on a machine for 9 yrs. I know that
management sometimes has other ideas.
> Will LinuxVserver do the job for us?
so far yes.
> If so, is there a 'best model'? I suspect the NAT model would be what we need.
The main problem with LVS-NAT is that it's a little touchy
with respect to firewall rules. Just add them one at a time
and be prepared to back out if they don't work. See the
HOWTO.
> The control box would be a 2 processor dual-core opteron so it effectively
> would have 4 processors and maybe 8gb or more ram.
SMP doesn't get you much in a director. A director is just a
router with slightly unusual rules. It's not doing much
computation. dual-core opterons don't have any more
bandwidth to memory than do single cores so you only get
more performance with applications that run out of cache.
You only need about 200bytes/connection, so you can have
8G/200 simultaneous connections - is that enough :-)
> Do you think we could get away with one 'control' box considering the
> bandwidth usage?
two if you ever think your box may go down or have to be
taken off-line for planned maintenance.
Joe
--
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!
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