I don't want to drag this into a long thread, but note the original says "the system should survive just about anything short of an act of God", and suddenly you are talking about a reliable server and a few switches. These are quite different things. I have yet to see a 5 x 9's server room. Fire, mechanical damage and other factors will normally keep the location itself well below 5 x 9's. Think "system" instead of "server equipment", and the picture looks very different. Even for a single PC type server, downtime due to telecoms lines, power problems, fire, flood, typhoon damage, theft and a mass of other stuff mught well exceed the server unavailablility itself. I've seen many servers not fail in 5 years. I have yet to see the best location go that long without causing at least one substantial period of downtime. 5 x 9's allows about 6 minutes downtime a year. That means 100% of all failures must have automated failover, as manuals repair could never be achieved so fast. Physical diversity if essential for that.
Regards, Steve
Chris Albertson wrote:
--- Steve Underwood <[EMAIL PROTECTED]> wrote:
WipeOut wrote:
Granted five 9's is never easy but in a cluster of 10+ servers the system should survive just about anything short of an act of God..You do realise that is a real dumb statement, don't you? :-)
A cluster of 10 machines, each on a different site. Guarantees from
the power company - checked personally to see that aren't cheating - that
you have genuinely independant feeds to these sites. Large UPSs, with
diesel generator backups. Multiple diverse telecoms links between the
If he says "cluster" he likely means 10 servers in one rack. But still you are right. It is all the other stuff that could break. You will need paralleld Ethernet switches (Yes they make these, no, they are NOT cheap.) you will need some kind of fail over. The switches can do that for you. (do a google on "level 3 switch")
It's the level three switches that make .99999 possible but half or more of your hardware will be just "hot spares" so it really will take a rack full of boxes
Each box should have mirrored drives and dual power supplies and each AC power cord needs to go to it's own UPS
Has anyone tried to build Asterisk on SPARC/Solaris? One SPARC
server is almost five nines all by itself as it can do thinks
like "boot around" failed CPU, RAM or disks. I've actually
pulled a disk drive out of a running Sun SPARC and applications
continoued to run.
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