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D.H. Brown Associates Attacks Linux
Scott Stevenson
writes "A News.com article describes a study which
dings Linux for poor SMP support, access to only 1 or
2GB of memory, and lack of clustering. Of course, it
doesn't say anything about NT's uptime issues on a
per-machine basis." Also says that hard data
isn't available on Linux being reasonably crash proof.
Windows NT Server Enterprise Edition can support user address spaces up to 3GB for specially made executables. Vanilla Windows NT allows user address spaces of 2GB. I'm not positive, but I believe NT can use a full 4GB of physical RAM. I've also heard that there is a really obscure version of NT that employs some sort of hoarfy paging scheme to use the x86's 36 bit addressing mode for physical RAM (in my opinion this feature is quite useless). Note that I hate NT.
x86 Linux has a 960MB user address space limit in a default kernel. It is possible to recompile a kernel to allow 2GB of address space per process. Linux has a tradeoff between physical memory installed and user process address space, their sum cannot exceed 4GB. Hence allowing 3GB of address space for user processes limits you to 1GB of physical RAM making this kernel configuration mostly useless.
My understanding is that Linux on 64 bit Alpha encounters difficulties around 2GB of physical memory due to PCI limitations. This doesn't sound that fundamental an issue, but it isn't a simple kernel recompile to fix it. Hopefully this will be ironed out soon.
Brian Young
bayoung@acm.org
Linux has a 4GB address space. One gigabyte is dedicated to the kernel.
WinNT cannot give 4GB to an application; that is
another lie. You need a special configuration of NT server just to have as much memory as what Linux makes available.
Secondly, Linux is a 64 bit operating system on 64 bit machines. It's a pure lie to say that some commercial UNIX can have 128 gigabytes of memory and compare that to Linux on Intel. I mean, for crying out loud, doh!
Missing from Linux are high-availability features that would let one Linux server step in and take over if another failed;
I'm not an expert on the subject but I've seen the high-availability howto at www.linux.org/help, so I know it's possible. Can somebody else comment on the subject?
full-fledged support for computers with multiple processors;
uhhm, did they even test this??? Last I checked Linux beats the crap out of NT on SMP...
and a "journaling" file system that is necessary to quickly reboot a crashed machine without having to laboriously reconstruct the computer's system files.
OK, that's true. Linux doesn't have jornaled file system. On the plus side, it doesn't crash very often... NT does have a journaled file system, but for some reason it took longer for NT to test the file system after the crash then for Linux to run fsck after the maximal mount count.
Currently Linux can't use more than 2 gigabytes of memory, and in some cases only 1 GB. Windows NT, on the other hand, can address 4 GB of memory
This is either a deliberate lie or a lack of knowledge (or both). First notice that he doesn't specify the hardware. It is assumed that there is only x86 in the world. Also notice the difference between "use" and "address". Linux *can* address 4 gig of RAM on x86, just like NT. The memory is split between kernel and user memory. By default the split is 2-2, but you can change it to 1-3 (1 for kernel 3 for user) by recompiling the kernel. NT works in *exact same way* with only one difference: you can't recompile the kernel. In order to get a 1-3 split you need to buy "enterprise edition".
Now, Linux also runs on 64 bit platforms, such as Alpha, SPARC and PPC, and it can take full advantage of 64 bit memory architecture. On these platforms Linux can address 2^64 bytes of memory -- I don't even know how much that is...
NT also runs on Alpha. But (surprise, surprise!) it's memory model is 32 bit. That means that even on a 64 bit platform NT cannot address more then 4 gig of RAM!
This whole article is pure BS. Notice that they pretty much just say "Linux sucks" without thorough comparison of any kind. Does anybody know where to send email for rebuttal?
___
If you think big enough, you'll never have to do it.
Data point - I'm aware of a couple NT boxes, and one Solaris x86 with 2GB. So its more like 99.5%.
While that may be top end now, look forward a few years, and it will be much more common to see this amount of memory on x86.
I'm not really aware of the issues involved in this, but I'm sure if turns out be a problem with Linux, they can slipstream a fix in to 2.3.666 or whatever. Commercial operating systems would probably do it at a major version upgrade, which NT won't see for a while after 2000 finally ships.
--
Business. Numbers. Money. People. Computer World.
It's true that Win2000 junks the Domain security model, but that has nothing to do with high availablity or journaling.
(A WinNT Domain is a common list of user/groups shared by a number of computers for login and ACL purposes.)
--
Business. Numbers. Money. People. Computer World.
It seems news.com provided an review of a review...
It's pretty bad that their report, news.com's, is uneven, though it highlights both strength and weakness. It doesn't explain their own reporting, much less Brown's.
Someone mentioned the pdf; is it available?
You have to pay for the real report... and there's a form I just filled out for an executive summary...
I can accept their claim that for 'enterprise computing' that other unices beat it, but not that 'Windows NT holds an advantage'. Price/performance, stability, and interoperability, from hearsay all over the web, seems to be Linux's strength against NT deployments.
Linux definitely seems to lack in robust SMP, or as they say, 'non-trivial SMP scalability', except I'm not so sure that NT qualifies. Isn't NT limited to 2 or 4 processor Intel solutions, which are themselves not quite so hot for enterprise level computing? As compared to bigger Sun or Alpha solutions? Maybe someone can correct me and tell me about a distribution of NT that runs on 32 processor Intel or Alpha machines at a reasonable cost and at reasonable performace and up time?
As for journaling, high availability clustering and such, I guess that much is true or under development... But I still don't believe that they think NT satisfies their requirements for an enterprise level computing solution!
Anyone care to correct me?
AS
-AS
*Pikachu*
The fact of the matter is that Linux's SMP support isn't on par with Solaris' (4 CPU's vs. 64), Linux's high-availability clusters aren't on par with *any* commercial UNIX (yet), and Linux's filesystems aren't journaled. (yet)
Some day (Kernel 2.4/3.0) all these features will probably be there, but let's not start touting vapourware over other solutions. Open source can only combat FUD if the code IS THERE. Right now, it isn't.
"Use the right tool for the right job" - Linux [on Intel especially] isn't it for sites that need extreme scalability & high availability. (A Sun Ultra 10k, AS/400 parallel cluster or S/390 mainframe is better suited to those environments.)
Ditto for sites that need to run a transaction processing monitor (like BEA Tuxedo) or a high end application server (like Apple's WebObjects). Though, this is changing... I think BEA is thinking of a Linux port... and WebObjects on Mac OS X Server is pretty sweet.
[ though not 100% open source, but nothing open source comes even close to Tuxedo or WebObjects in terms of performance, elegence, reusability & developer tools. Perhaps the GNUstep project will adopt the WebObjects framework as another pet project.. ]
-Stu
Executive summary pdf link:d f
http://www.dhbrown.com/dhbrown/downldbl/linux.p
This contains FUD at higher level than that found in ZDNet.
Pay attention to how SMP and Linux is "covered" on pages 7-9
begin quote:
By boosting the number of locks to somewhere between 10 and 100, the Linux 2.2.5 kernel used by OpenLinux 2.2 should improve its SMP scalability somewhat. But while Linux 2.2 systems can boot on an SMP system with up to eight processors, useful SMP deployment at current levels of granularity has not yet been proven. Little industry-standard or even proprietary benchmark evidence has emerged that demonstrates the performance improvements of
database or Web server applications running on SMP systems under any Linux distribution. Although Linux has been tested on a variety of SMP systems, booting on eight-processor systems is far
different from demonstrating improved performance on mixed throughput workloads or multi-threaded database applications.
:end quote
Rather than doing RESEARCH and STUDY, they merely report the # of CPUs used in previously published NT and Commercial Unix benchmarks. (They do not print the actual benchmark results here). The number of CPUs used is a virtually useless comparative benchmark. Since they selected two benchmarks where there are no previously published Linux results, they report nothing for Linux. This is used to portray Linux as hopelessly inferior, without actually having to do any work. Check out how they put Linux at 0 CPUs on the graphs. I thought only Microsoft would do something so obviously corrupt and shameless.
Method: Claim Linux is inferior. Do no benchmarking yourself, but make the lack of data for Linux sound ominously bad. Put in some fancy graphs of useless values selected only for their ability to make Linux look worthless at first glance.
It is amazing people will pay DHBrown for a report of this quality.
Here's the article.