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

-----Original Message-----
From: [email protected] 
[mailto:[email protected]] On Behalf Of Address
Sent: Tuesday, December 15, 2009 8:12 PM
To: U2 Users List
Subject: Re: [U2] Unidata 6.1 Replication

Double-Take replicates byte by byte.

--- On Tue, 12/15/09, BraDav <[email protected]> wrote:

> From: BraDav <[email protected]>
> Subject: Re: [U2] Unidata 6.1 Replication
> To: "U2 Users List" <[email protected]>
> Date: Tuesday, December 15, 2009, 10:56 PM Someone needs to write an 
> i/o agent, so U2 can be used with products like Double-Take and keep 
> record level integrity.  Anyone with c++ experience out there?
> 
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