Microsoft Janus

nadador writes "Apparently, Microsoft is readying an enterprise class clustering and failover version of Windows 2000. Techweb, and Microsoft, I'm sure, seem to think this is going to be a "Unix Killer". It also mentions Linux as a driving force in making Windows truly enterprise class software" It actually sounds quite impressive. I can't wait to see what some of the upcoming HA (high-availability) enhancements for Linux will look like.

Comments

Micorsoft Rules the world!!

[gerald_holmes]

Hey everybodys this is just one more good things that Micorsoft is does and it goes to shows that Bill Gates is a super genius smart man who knows alots of stuff and things.

Here I prooves that Micorsoft is really really very very good: http://www.freeyellow.com/members7 /geraldholmes/index.html

The professional view

[Salamander]

I was one of the principal designers and implementors of both the cluster manager and lock manager for HACMP/6000 version 3.1 (which, BTW, supported 8-way symmetric failover) back in '94, so maybe I'm qualified to comment on some of this.

First, about MS. The consensus opinion among people who really know HA is that Wolfpack was and is the most pathetic piece of junk ever. The prevailing theory is that they quite deliberately announced it knowing that it was junk, to scare off anyone (such as my employer at the time) who might try to produce their own NT HA solutions.

This Janus project is just another step in that direction. 64 or 256 nodes? Yeah right. There are several reasons other HA solutions typically only go up to eight. The main one is that nobody really wants a single cluster that big. It's a total management nightmare. What customers actually want to do is set up multiple independent clusters of a reasonable size, and perhaps manage them all from within a common framework, but that's not the same as a single cluster. There's just no benefit to offset the cost of setting up failover relationships that deep and complex.

Another reason you don't see HA clusters beyond eight is that it's all but impossible to devise protocols (membership, hearbeat, consensus, and so on) that scale that high and yet still handle the simple cases efficiently. Just avoiding all the race conditions in eight nodes booting and trying to join the cluster at once is incredibly difficult. If you don't think it's that hard, try it. Have fun. Come back after you've failed, and we'll talk. ;-) MS has so far exhibited nothing but the most startling ignorance and incompetence in these areas so far, and the idea that they'll suddenly leapfrog the established experts like this is just bunk. It's far easier to believe that they're deliberately making false claims to scare off the competition...again.

Now that I've bashed MS HA, a few words about Linux HA. It's as pathetic as MS. We have some very basic heartbeat code, and a few other scattered bits and pieces, but that's it. There's practically no fault identification to distinguish different types of failures so that one can respond differently to an adapter or network failure as distinct from a node failure. There's no lock manager. Many of the people working on the designs are only beginning to grasp the basic problems, and they're months if not years from actually implementing industrial-strength solutions. I'm on the mailing list (or I was, before I moved and had to give up my cable-modem account), I see the traffic, and it's Just Not There. I'm sorry, and I wish I could spare more time to contribute more of my own hard-won experience to the project, but that's just the way things are.

jdarcy@emc.com, until I get a new home account