Thank you for your detailed explanation. It helps a lot.
Iulia
On 05/02/2011 04:57 PM, Michael Segel wrote:
Hi,
That's actually a really good question.
Unfortunately, the answer isn't really simple.
You're going to need to estimate your growth and you're going to need to
estimate your configuration.
Suppose I know that within 2 years, the amount of data that I want to retain is
going to be 1PB, with a 3x replication factor, I'll need at least 3PB of disk.
Assuming that I can fit 12x2TB drives in a node, I'll need 125-150 machines.
(There's some overhead for logging and OS)
Now this doesn't mean that I'll need to buy all of the machines today and build
out the cluster.
It means that I will need to figure out my machine room, (rack space, power,
etc...) and also hardware configuration.
You'll also need to plan out your hardware choices too. An example.. you may
want 10GBe on the switch but not at the data node. However you're going to want
to be able to expand your data nodes to be able to add 10GBe cards.
The idea is that as I build out my cluster, all of the machines have the same
look and feel. So if you buy quad core CPUs and they are 2.2 GHz but 6 months
from now, you buy 2.6 GHz cpus, as long as they are 4 core cpus, your cluster
will look the same.
The point is that when you lay out your cluster to start with, you'll need to
plan ahead and keep things similar. Also you'll need to make sure your NameNode
has enough memory...
Having said that... Yahoo! has written a paper detailing MR2 (next generation
of map/reduce). As the M/R Job scheduler becomes more intelligent about the
types of jobs and types of hardware, the consistency of hardware becomes less
important.
With respect to HBase, I suspect there to be a parallel evolution.
As to building out and replacing your cluster... if this is a production
environment, you'll have to think about DR and building out a second cluster.
So the cost of replacing clusters should also be factored in when you budget
for hardware.
Like I said, its not a simple answer and you have to approach each instance
separately and fine tune your cluster plans.
HTH
-Mike
----------------------------------------
Date: Mon, 2 May 2011 09:53:05 +0300
From: [email protected]
To: [email protected]
CC: [email protected]
Subject: Re: Hardware configuration
Thank you both. How would you estimate really big clusters, with
hundreds of nodes? Requirements might change in time and replacing an
entire cluster seems not the best solution...
On 04/29/2011 07:08 PM, Stack wrote:
I agree with Michel Segel. Distributed computing is hard enough.
There is no need to add extra complexity.
St.Ack
On Fri, Apr 29, 2011 at 4:05 AM, Iulia Zidaru wrote:
Hi,
I'm wondering if having a cluster with different machines in terms of CPU,
RAM and disk space would be a big issue for HBase. For example, machines
with 12GBs RAM and machines with 48GBs. We suppose that we use them at full
capacity. What problems we might encounter if having this kind of
configuration?
Thank you,
Iulia
--
Iulia Zidaru
Java Developer
1&1 Internet AG - Bucharest/Romania - Web Components Romania
18 Mircea Eliade St
Sect 1, Bucharest
RO Bucharest, 012015
[email protected]
0040 31 223 9153
