Brad and John,

[ad]
Since, we work with both UD and UV we found replication is not the same.  We
wrote a simple Java program
that runs using UOJ and does the replication to one or many sites.  The
software can even replicate
from Universe to Unidata or the other way.  Additionally, we added support
for TCL/ECL commands such as 
CREATE.FILE, BASIC, and most others.  We don't have any problems with any
release of Unidata 6.0 or greater or
Universe 9.6 or greater.  We don't have any issues with dynamic or hashed
files since everything
is replicated at the record level.

This is all part of our amazing U2WebLink(tm) product that runs on Apache
Tomcat.  We even added
native support for PHP.  The product handles thousand upon thousand of
transactions per hour
without even a hiccup at our clients for many many years.
[/ad]

Regards,
Doug
www.u2logic.com/tools.html

BTW: We heard that soon UD and UV will be using the same replication engine.

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of John Hester
Sent: Tuesday, December 15, 2009 11:01 PM
To: U2 Users List
Subject: Re: [U2] Unidata 6.1 Replication

Brad is right.  You can get bitten by OS-level replication with U2 because
hashed files require more than one write when a record has to go to overflow
space.  If the primary box crashes when only one of these writes is done,
the secondary box will have a corrupted file.  There are also issues with UV
dynamic files (don't know about UD) because some of the file structure
information is cached in memory and not immediately flushed to disk.  We do
OS-level replication on UV and got around these issues by sizing all files
to use no overflow and only using dynamic files for temp report work files.

-John

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