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High Availability Clustering
Christopher
Cashell writes "Everyone knows about Beowulf High
Performance clusters, but it's often remarked that these are
impracticle for most business uses, and that High Availability
Clustering is still lacking. It looks like the guys at
TurboLinux are working on fixing that. First
seen on freshmeat"
High availability means two or more servers act as a single logical server, so if one node fails (i.e., root disk crash, power supply failure, etc.) the other takes over for the cluster, and services (web, nfs, dbms, etc.) continue.
The takeover requires importing the data disks (dual initiated SCSI arrays attached to both servers), and starting the services on the surviving node.
The heartbeat is the way each server tells the other, "I'm alive". When one server stops hearing it, it tries to take over. Sometimes, there is a serial connection that is used to force the non-surviving node to an init 0 state.
This is the hard part, since if a NIC fails, both could assume they are in charge (called split-brain), and kill each other off, or both continue to run.
If all works well, the failover takes from 30 seconds for a simple configuration to several minutes on a complex configuration.
Hang in there Ellis.
People who set themselves up as judges tend to become arrogant SOBs with no sense of humor.
I'm looking for a way to invert the ratings scheme that I only see post that have a 0 or less rating. I get tired of high-falutin long winded garbage and like short humorous posts better.
Humor seems to be that last thing these self-appointed 'moderators' understand. They're too busy hiding the kids (Linux Loonies) so as not to offend the suits (don't ask me why).
Well, the news is that they are looking for sponsors who may also decide on the license. Would be a chance for those who want to see it GLPed, wouldn't it?
Excuse my gross ignornace (i know, i know.... :), but what exactly is the difference between the bewulf clusters that are all the rage at the moment and a "High Availibilty Cluster" - Jaymz, who is an ignoramus
Commodore 64, Loading up the dance floor!
Check it out, I think they are prevented from using GPL for legal reasons (government, powers that be???).
In this case, handing MOSIX over to another team that can relicense it is the way forward.
Hi, I'm familar with and impressed by the eddieware project. One thing about high-availability solutions is that vendors require intensive hand-holding, enterprise 24x7 global support, and commercial technical integration.
We're simply trying to help Linux get into the enterprise. There is no need for competition. I hope we all succeed in our own projects. If every project succeeds, Linux in general becomes stronger and this is what we really want.
Hi, as far as I know, the monitoring code was all developed by TurboLinux and is all original. The kernel development also diverged from Wensong's OpenSource project and future versions will continue to diverge. Since the kernel patches will be under GPL, it is possible that Wensong's project may take in the TurboLinux work. Though, that would be up to them.
Another thing to consider is that since all our development work on the kernel patches are and always will be under the GPL, all OpenSource projects will benefit. In version 2.x of the cluster product, we will completely rewrite the kernel modifications to drastically improve routing performance and will contribute this back to the community so that all can benefit.
This person's comments are not being moderated down. Check out the user's info, this person has posted 299 (!) comments in the last few weeks, and so many of them have been marked down to -1 (usually for good reasons) that their comments now default at score 0 just like an AC.
it looks like some other company other than Redhat is starting to give back to the linux community. Redhat has give us gnome and rpm, now TL is giving us improved clustering.
Only 'flamers' flame!
Apparently the only reason that they `needed' not to release it under GPL was that they wanted to hinder undesirables getting supercomputers. ... but hey - its not my code.
Thus they want to release it as binary only module limited to (presently) six nodes.
I don't see the logic in that myself
I would like to see a cluster of the new playstations, when the come out.. 128 bit RISC processor running at 300mhz. 6.4gflops!!!!
=>
www.playstation.com
"Windows 98 Second Edition works and players better than ever." -Microsoft's Home page on Win98SE.
I ate my tag line.
-=Ellis (D)25=-
Why do people think Red Hat are evil? Redhat release all the things they develop under the GPL. Companies like this, who have built themselves up by selling Linux (ie little cost of R&D), then make binary shareware to put in their distros, which should be shunned.
Almost every binary shareware distro is based on RedHat as well! Look - SuSE( Probably the worst), Caldera, TurboLinux... why do people use this stuff? So they can make more binary-only things? If you want a corporate backer to your distro, use RedHat. If you want a totally free & professional distro, use Debian. Whatever you do, *don't* support companies who are just proving that its ok to leech off the community.
Interesting... looks like they will honor the GPL on some of it. Anyone know if the monitor and config will be based on the same GPLed material?
Help achieve Liberty in your lifetime - join the Free State Project - http://www.freestateproject.org
Web service is one of the easiest things to make highly available. There's very little server-side state, reads predominate over writes by a couple of orders of magnitude, etc. In fact, the TurboLinux white paper even states that they don't support any form of data consistency, so your traffic had better be _all_ reads. Yuk. They also talk about the "active router" providing "fault tolerance", indicating that they don't know the difference between fault tolerance and high availability.
Some of the monitoring code is useful in other contexts, but they got that from somewhere else. As near as I can tell, PHT's own technical contribution is near zero.
Slashdot - News for Herds. Stuff that Splatters.
Not quite a fork off, more of a fork on :) We started out differently, but ended up using and modifying the kernel patch for the virtual server project. FYI we are doing most, if not all, of the development on the 2.2 patch, afaik.
Later,
Justin
Read the reply to the 'GPL versus $1,000' post for more detail, but we haven't declared closed-source yet, as the FAQ says we have not decided on Licensing for the monitoring and configuration portions yet (as it puts it, this basically covers tlclusterd which does load balancing, makes sure all the other hosts are up using more than just a ping - it actually tests the web server, and tlclusteradm, the basic admin tool.. the TurboNetCfg module that admins the CWS is open-sourced, as is the rest of the Turbo* config tools).. stay tuned, as I said, for our decision on the licensing for these tools.
:)
Any questions? e-mail me : justin@turbolinux.com, we're out to make people happy!
Later,
Justin
Most of the customers for high-availability clusters are corporations who use them in mission-critical systems. To them $1k/node is nothing.
As with all GPL'd software, you pay money for the intangibles-- tech support, documentation, and, in this case, value-added tools. When nodes running your stock market go down, you want to be able to pick up the phone 24x7 and get help real fast.
MOSIX has actually been posted to slashdot before, and was the subject of a rather intense discussion.
They're project is a kernel module that requires kernel modifications, however, according to Linus's decision, this means they have to release the whole thing under the GPL if they decide to distribute the module. Last I heard, they hadn't decided what they were going to do about that, yet, as they wanted (needed?) to distrbitute it as binary only.
Topher
ok, GPLed!... And at $1000 a node, someone will write a GPLed monitor and config portion real quick to match it.
Wondering why they are charging so much....
Help achieve Liberty in your lifetime - join the Free State Project - http://www.freestateproject.org
Yesterday btw there was an eddieware press release
that their open source web stuff will be doing a
real live test for the next cricket series.
Well cool
There is some really good stuff on Virt Servers at http://proxy.iinchina.net/~wensong/ippfvs/ . I belive that the pacific tech distribution was a fork off of this project.
I'm a bit confused. OK there are many Web server very important but high avaiabilty is not only for Web.
In the industry HA is more important for DBA, TP monitor and application server than Web? Doesn't it?
---Pila---
I've linked this site to our community home page.
The statement that it is simply repackaged is incorrect. As the development continues, we'll always release the source for the kernel routing features and hopefully help the progress of the free software projects.
Pacific HiTech is putting this out as closed source. Pretty neat. The community does all the testing and they get to keep all the source. Not very friendly.
My computer, my way. Linux
--
Howard Roark, Architect
Howard Roark, Architect
I believe in a Man's right to exist for his own sake.
There are a whole pile of solutions see
http://www.henge.com/~alanr/ha/
I guess thats a very underpublished URL 8(
Well, everybody's talking about Beowulf, about High Availability. But nobody dares to talk about MOSIX, a Linux Kernel Module developed at an Israel University. It supports things like application-transparent adaptive load balancing, memory ushering and things like that. The only problem: not free up to now. But, wait! They are currently looking for a sponsor for maintainance and further development. This sponsor(s) may also choose the license, too. Check this one: MOSIX Homepage. Tried to post it to slashdot wo times before, but they didn't seem to like it ... :(
Eddieware does DNS load balancing (and hence isn't bottlenecked like the Linux Virtual Server Project), LAN load balancing, IP migration and admission control. In addition to linux 2.0.x and 2.2.x it works under FreeBSD and Solaris. Checkout http://www.eddieware.org .
Checkout the Eddieware press release at www.eddieware.org/txt/press990503.html . Funny how this didn't get a mention in the main slashdot articles but a closed source solution does!