Re: Using two boxes to share the load via ddm files

I've used and am using a fair amount of DDM - more than I'd like actually.
I'm currently using DDM over SNA (AnyNet). The performance is adequate - not
quite as good as being there, but acceptable. Once thing to be careful of is
how you make and break DDM connections. For instance, you have a client
program on system A communicating with a server program on system B.
Accessing data from remote system B is going to be pretty fast - as fast as
DDM and Anynet allow. Now take 300 client programs accessing system B.
Things will slow down appreciably, because basically you have two ways of
handling conversations - keep the conversation going, even if there's no
session; or drop the conversation when the session is done. The first way
causes the number of available modes to be used up, causing timeout errors
The second way is slower because of the dropping. We had a problem with the
first method and moved to the second. It's slower, but it works.

You might also look into data queues between the systems or remote SQL using
CONNECT TO. These will impact the system, but not as much as several client
programs accessing a remote system.

On 12/1/06, Rick DuVall <R_C_DuVall@xxxxxxxxxx> wrote:

Hi group,

        Two iSeries (or whatever) boxes hooked together with gigabit
ethernet.  Box A accessing Box B through ddm for certain DB file access -
both random and sequential.  What are the considerations in regard to
performance?  I have never experienced ddm before and have no idea how
this
will perform.  Does anybody have any real-world experience they would be
willing to relate?  Can I expect this to perform up near the abilities of
both machines?

        I am probably not asking this very well.  I have read some of the
documentation and understand roughly how it works.  There seems to be two
ways to connect?  Sna and Tcpip?  Which is fastest?  How big is the hit on
the 'Target' machine for data access?  I'm just trying to get a feel for
how
this sort of thing would work and I know that the final answer has to be
'That depends' but I would appreciate any information, anecdotal or
otherwise anyone might be willing to share.


Thanks

Rick DuVall
Systems Manager
Dealer's Auto Auction of Okc
1028 S. Portland
Oklahoma City, OK 73108
(405) 947-2886
rick@xxxxxxxxxx
http://www.nothingisreal.com/dfki/no-word


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