Hi All,
I haven't compared Linux vs. Windows in some time, but in the past when
comparing, a linux based instance seemed to require more ram than the
same region running on a windows machine.
We at 3rd Rock use only windows for our grid and centOS for our web server.
It is true that I personally am much more comfortable using windows than
I am Linux, but I am not against Linux.
In our early days back in '08 I had originally started 3rd Rock using
Linux, but changed over to Windows as I am more comfortable with that
platform.
This topic has all the dangers of quickly turning into a Ford vs. Chevy,
or coke vs. pepsi argument, so to be fair, some may prefer linux over
windows for different reasons, but the reason 3rd Rock runs windows is
that my personal observations and tests revealed to me that opensim on
linux uses more ram "And" I am more comfortable with the windows platform.
~Butch
On 10/11/2014 4:06 PM, Dahlia Trimble wrote:
I have noticed decreased performance when running OpenSimulator in a
VirtualBox VM vs. running it on the host. Usually it's when there is a
lot of I/O operations, such as high database activity or networking
load. I've also seen issues when a lot of timers are used in scripts.
This makes sense as VIrtualBox adds significant overhead to such
operations.
I've seen much better performance using OpenVZ, however OpenVZ is
harder to work with as it's not really a virtual machine but rather
more of a constrained operating environment. It does not add as much
overhead to I/O operations as a true virtual machine would. It also
did not seem to suffer from the timer issues I've seen in VirtualBox.
I've used OpenSImulator on a variety of virtual servers now for
several years and in general it does work reasonably well for smaller
use cases. I would not consider using anything but bare metal or
OpenVZ for any regions which were expected to have high performance
and service many users simultaneously.
In general I've found Windows+.NET to be much more robust than Mono. I
do see problems occasionally on Linux+Mono but I tend to blame Mono. I
have experimental code which can crash and burn any Mono version I've
tried to date, yet runs flawlessly on .NET. This code creates and
dereferences millions of very small objects and when run on a Mono
installation will leak memory and crash with out of memory errors.
I've discussed it with several Mono devs on IRC and the consensus was
a possible bug in one or more of the Mono runtime libraries. I've also
seen a lot of random Mono crashes that I just never see in .NET while
running the same sim under similar load conditions.
While in general I believe .NET to be a more robust operating
environment than mono, the lower cost and ease of use of Linux for
server-like applications usually means I use Linux servers for running
regions. I usually use Windows exclusively for OpenSimulator
development, which may be a reason why I tend to notice such
differences. I don't really have any documented empirical evidence to
support my reasoning other than having some code which will crash
Mono. Most of my rationale is based on observations during my
OpenSimulator development and deployment activities over the past
several years.
On Sat, Oct 11, 2014 at 8:46 AM, Maxwell, Douglas CIV USARMY ARL (US)
<[email protected] <mailto:[email protected]>>
wrote:
The MOSES project ( http://militarymetaverse.org/ ) has
experimented with a number of different Open Simulator deployment
methods. The grid is currently has access to a blend of 5 Dell
PowerEdge R815 servers and one Dell PowerEdge R220. The R815's
are virtual machine servers and the R220 is a small Linux host
used to serve up to 10 sims. On the R815's we can stand up any
operating system we wish to experiment with using virtual machines.
Currently, our favorite installation method is using Ubuntu
Linux. This is only for convenience as all of the dependencies
are available as packages. On Ubuntu, we can start with a bare OS
install through completely functioning MOSES grid in about 3
hours, including compiling from source. Less time when dealing
with binaries.
Our Complete Instructions Here:
http://militarymetaverse.org/wp-content/uploads/2014/10/MIAB_Installation_Instructions_using_Virtual_Box_and_Ubuntu-141006.pdf
We have worked with CentOS, but it is a lot of work. Mostly
because of the bootstrapping needed to get Mono and its associated
packages working. It is easy to make mistakes and you can spend
hours troubleshooting. In the end, it seems to operate similarly
as Ubuntu.
The version of Windows we typically work with is the Army Golden
Master of Windows 2008 Server or Windows 7 AGM. The biggest issue
we deal with is just setting up the environment and being forced
to manually download and install all the dependencies. This can
take days. The Army version of Windows also has extra registry
values and network policies that pose configuration challenges.
Virtual Machine Performance Differences?
In our testing we have not *yet* found any measurable difference
in performance between Open Simulator deployed via VM or bare host
on any operating system. This has been independently verified by
our industry partners and other military labs using their own
internal hosts as well as Amazon EC2.
Operating System Performance Differences?
Unfortunately there are so many variables that affect open
simulator performance that anecdotal evidence to support Windows
or Linux simply don't hold up. Its not a simple matter of
comparing .Net to Mono. The operating systems are fundamentally
different, so a proper test would involve replicating the Open
Simulator servers as closely as possible on each. This would
require an initial benchmark test that has both Windows and Linux
servers using the same version of Mono, same version of Apache,
same version of MySQL, etc... on the same host configuration
(i.e. hardware or VM profile).
Any deviations introduce variables to the test that must be
accounted for. For example, only after the Windows vs. Linux test
has been completed and analyzed for differences can you then
introduce another variable of .Net vs. Mono and re-run the
performance benchmarks. The original Windows vs. Linux benchmark
is the baseline.
Douglas Maxwell, MSME
Science and Technology Manager
Virtual World Strategic Applications
U.S. Army Research Lab
Simulation & Training Technology Center (STTC)
(c)(407) 242-0209 <tel:%28407%29%20242-0209>
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