[Typo3-dev] Distributet Typo3 site, how to approach this?

[Martin Seebach]

Hi Georg,

Georg Rehfeld wrote:

> Looking into this direction it might also be a worth to look at MySQL
> clustering, which should be available even in commercial quality
> soon:

I don't know anything about MySQL clustering, but from what I read about 
it last night, it seems to me that by clkuster it means that a number of 
servers are interconnected in a highly relibale and very fast dedicated 
network, and appear to the outside as one computer.

If your customers sites are distributed across the world, notably 
seperated by the atlantic, your links will be high-latency and generally 
unreliable.

> As far as I can see with a cluster there is no dedicated master any more
> from the perspective of the application (the different Typo3
> installations).

You can also make circular replication. But the problem arises when 
serveral clients tries to write to the same target simustaneously. You 
could imagine two editors create a page within the same second, and both 
be given uid 345 by auto_increment. This would be trouble, and I donøt 
know enough about typo3 internals, much less MySQL internals. What I 
would do in your shoes, is to throw a bunch of money after a 
professional MySQL consultant and get this right. A corrupted database 
is really, really bad.

> However, with both approaches (simple replication or clustering), what
> is not replicated are all files stored in the filesystem: images,
> uploaded documents etc. 

This is where CODA comes in the picture. You have a distributed mount, 
say /coda on all you servers. When a file is created in this mount, it 
is advertised in such a way, that it will show up on all the other nodes 
in the CODA-network. When that file is then opened on one of the other 
noed, it is transfered, kept in cache, and accessed locally. I have no 
personnal experience with CODA, but it is designed to do excatly what 
you want need it to do in this case, and I've heard nothing but good 
things about it.
The bottomline is, that no matter what node the file is created on, it 
looks like it is local on all other nodes, and transferred transparently

Regards, and good luck,

Martin Seebach

-- 
Venlig hilsen
Martin Seebach