Coda File System

Large servers ...

From: Tomalla, Wolfram <>
Date: Thu, 21 Jan 1999 12:04:07 +0100

I'm from a company in germany that produces a controling
system for a lot of different processes eg. a powerplant
or a central controling of Coce mashines.

I thought about running a database (with ODBC and JDBC
drivers) on a coda filesystem to get a redundant data
holding. I think the problem will be that there will
be one or two large files (the database and the logfile)
and tese files are written to. So if always the whole 
file is copied to all servers if the database does
a fsync() it will be nearly impossible to insert any
data to the database without a timeout. But on the 
other hand if the database does an fsync() I have to
be sure, that all changes to the file are copied to 
the other servers. Else I do not have the redundant 
data holding I need to keep the date consistend even
if some hardware crashes.
I see the only possible solution in adressing and
copying the file in blocks of eg 4k.
Even if I look at my private mailfolder I see this 
problem. I acualy delete my old mail about once a
month. So there is also the point that closing my 
mailbox will take several minutes if it has to be copied
completely over the net to all servers.

Well I don't have problems in giving the servers for
our controling system gigabit networking cards, but 
I don't thing this is the right way to solve this problem.

Yours sincerly

Wolfram Tomalla
Received on 1999-01-21 06:06:37