Thanks for the scalability info. I had one more question: does the
vcld component benefit from multiple cores? In other words, is the
vcld component multithreaded?
On Sep 9, 2009, at 12:51 PM, Aaron Peeler wrote:
It's hard to put an exact number on it because of the different
types of resources that can be made available(vm,bare-metal,lab
machines), but we should be able to get theoretically close.
Correct - multiple management nodes is an important part of the
scaling. So the first question is how many resources can a single
management node support.
Additional things to consider are how the nodes get provisioned and
the usage profile(asynchronous or synchronous). Also this is
assuming one has robust web server, database, networking, storage
and management nodes. The network, storage and management nodes are
a big factor.
Provisioning options -
bare-metal vs. hypervised vs. stand-alone lab machines
*bare-metal - installing an image to disk using xCAT:
typically we have experienced anywhere from 150-200 blades per
management node for asynchronous use.
*hypervisor using vmware free server vs ESX/i with either persistent
vs non-persistent mode.
VMware ESX with network datastores for the vms and running in "non-
persistent" mode. One could probably get 1000+ vms per management
node maybe more. Again this assumes fast access/networking to
storage (10G ethernet or fibre), a nice storage array and running
20+ vms per esx server.
vmware free server - typically 5-10 vms per server
at NCSU we also use traditional lab machines when the university
labs close. This mode is only brokering remote access to nodes,
therefore no loading is going on. One could probably get 700+
machines per management node.
Usage Profile: asynchronous vs synchronous
synchronous usage is the most demanding usage, block allocations/
provisioning for a class, workshop or some other event that needs
many nodes at a single event.
asynchronous usage - users independently request nodes at any given
time. This is spread out over time and has a lower provisioning load
on the management node/s.
Since we(ncsu) don't have the infrastructure to confirm these
numbers this is just an educated guess based on past experiences
based on what we do have. I would feel comfortable saying that if
using multiple management nodes and an ideal HW setup, beefy blades
(multi-core, extended memory blades, high-end storage, fat-pipes,
etc), vcl could conservatively support several thousands nodes.
--On September 10, 2009 12:20:39 AM +1000 Sengor <seng...@gmail.com>
I'm not certain of the exact numerics, however I do believe support
multiple management nodes (vcld's) is an intentional scale-out
Perhaps some of the guys @ NCSU know this one, I believe their VCL
instance is currently the largest one in production.
On Wed, Sep 9, 2009 at 11:55 PM, Brian Bouterse <bmbou...@gmail.com>
I'm wondering what the scalability limits of VCL? What are the
the vcld component, and why do we believe they exist? Does the
have any scalability limits?
I'm trying to figure out what the reasonable number of VMs a
installation can concurrently support. What do you think and why?
OIT Advanced Computing
College of Engineering-NCSU