In our case it would be 10,000 users on a datacenter cluster. Running 3
active/1 passive, we end up with around 3400 users per node.
By the way, I don't consider myself any kind of authority on clustering or
exchange!
Regards,
Rob Ellis
Messaging Consultant
Service Delivery Solutions & Programmes
IBM Global Services
DDI: 01256 752845
Mobile: 07974 111867
Fax: 01256 754899
Email: [EMAIL PROTECTED]
-----Original Message-----
From: Webb, Andy [mailto:[EMAIL PROTECTED]]
Sent: Thursday, September 06, 2001 2:53 PM
To: Exchange Discussions
Subject: RE: [Exchange2000] Exchange Fault Tolerance
No, I didn't say they're a "flop". I said that expectations with respect to
clusters are often off target. I still don't have enough information to
recommend whether you should go forward with them or not. I suppose if you
hired Rob Ellis to implement it and provide training, you might just get a
successful implementation. :)
Some people /have/ been successful with clustered Exchange. Many have not.
"Success" however is an objective concept defined by the initial
expectations set and the ability to meet them. So, with mis-set
expectations, whether simply technical or vis-a-vis the skill of the people
involved. I don't think I'd make a production Exchange cluster the first
cluster in the environment in most cases.
Hosting 20K users on a DataCenter cluster is a pretty niche market. I
suspect that the due dilligence has been performed there and expectations
are pretty on target.
=======================================================
Andy Webb [EMAIL PROTECTED] www.swinc.com
Simpler-Webb, Inc. Austin, TX 512-322-0071
-- Way to go USPS Cycling Team and Lance Armstrong!! --
=======================================================
-----Original Message-----
From: "Peņa, Botp" [mailto:[EMAIL PROTECTED]]
Sent: Thursday, September 06, 2001 5:07 AM
To: Exchange Discussions
Subject: RE: [Exchange2000] Exchange Fault Tolerance
Thanks, sir Andy.
I have seen firewalls clusters and web farms in action. And was quite very
impressed. None yet for Exchange though. In your case then, can we fairly
say that Exchange clusters are a flop (or "forget it" as some would say)?
You did not answer as to whether we should wait or "forget it -it is
impossible for exchange to attain 5 9s in a cluster, ever" (again, I am just
asking your opinion since you are well respected in this list).
Thanks,
-botp
-----Original Message-----
From: Webb, Andy [mailto:[EMAIL PROTECTED]]
Sent: Thursday, September 06, 2001 11:49 AM
To: '"Peņa, Botp"'
Subject: RE: [Exchange2000] Exchange Fault Tolerance
Definitely 1. 2 is a matter of your expertise and the ultimate roi of the
clustered solution in your environment.
I think clusters have their place, but it's more with applications which
behave more like the clusters do. People seem to be unsatisfied with their
clusters in my experience once they've seen them in action.
=======================================================
Andy Webb [EMAIL PROTECTED] www.swinc.com
Simpler-Webb, Inc. Austin, TX 512-322-0071
-- Way to go USPS Cycling Team and Lance Armstrong!! --
=======================================================
-----Original Message-----
From: "Peņa, Botp" [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, September 05, 2001 10:39 PM
To: 'Webb, Andy'
Subject: RE: [Exchange2000] Exchange Fault Tolerance
Thanks, Sir Andy. Very helpful and well said.
To summarize your point (in so far as I can comprehend):
1. clusters add complexity
2. clusters are risky
Do your statements apply to clusters in general, or is it only for Exchange
(or as to the current Exchange clustering stage)? I am asking since we might
abandon the plan totally or just wait for another year or years....
Thank you again,
-botp
-----Original Message-----
From: Webb, Andy [mailto:[EMAIL PROTECTED]]
Sent: Thursday, September 06, 2001 3:27 AM
To: '"Peņa, Botp" '
Cc: '[EMAIL PROTECTED]'
Subject: RE: [Exchange2000] Exchange Fault Tolerance
Knowing no more about your business than what is in that note, I'd say
you're needlessly adding complexity to your environment which will not
result in the net availability increase you forecast at the low cost you
expect.
There is downtime associated with a clean node swap in a clustered
environment. Is 2x that downtime significantly less than that required for
a service pack install? Not usually. Does it let you apply one or more
hotfixes with less impact to the users? Not usually.
Running a clustered environment also means you need to be running a
clustered test environment so that you can simulate all these rolling
upgrades. Having that AV upgrade hose an entire node of your cluster is not
significantly better than having it hose a standalone server, and you may
not know that things are bad until you've moved the active node back to the
already upgraded server.
As noted above, I don't know enough about your environment to make this a
firm recommendation. To spend the time to get that familiarity, I'd likely
want a consulting contract. Clustering is not for the faint of heart, and
it is not to be used without serious thought to the whys and whatfors. Do
you really have a business need for mail to every user to be available five
nines or more? You may, but you would be one of a very few. I'd rather
take that second server and use it for disaster recovery drills and testing
of all the software upgrades you mentioned. Then my actual downtime would
be minimized by having a known, tested, and understood upgrade process that
could proceed quickly. Most service packs and hotfixes are 10-15 minute
activities if planned and practiced.
$0.02
Andy
Andy
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unauthorised - please notify the sender by return and delete the message. Any
representations or commitments expressed in this email are subject to contract.
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