At 1:56 AM -0400 8/8/03, Craig  wrote:

>I am running on MPE/iX 7.5 exp1 and all reactive patches.
>
>I am just testing. I understand the difference between Jumbo files and
>largefiles, but what is the difference in performance etc...
>
>Also, how do I enable it using Adager, do I need a special version of
>Adager?

Jumbo datasets are multi-file datasets to support datasets with more
than 4 gigabytes. They consist of a "control file" and two or more
"chunks," each one with a size of up to 4 gigabytes. The control file
has the original (single-file) dataset file name, each one of the
chunks has the dataset file name with a file extension ".001",
".002", etc.

LargeFile datasets (also called LFDS in the MPE/iX 7.5 Communicator)
are single-file file datasets with a size up to 128 gigabytes. LFDS
allows you to use dynamic expansion on datasets with maximum
capacities larger than 4 gigabytes.

Kevin Cooper's presentation on 7.5 performance discusses the
potential performance implications with LFDS. The main concern is in
how single-threaded checkpoints in the transaction manager affect
your overall application performance.

The Adager default is to use jumbo datasets when a dataset exceeds 4
gigabytes. The reasons for this default are historical as well
technical. Once you enable a database for LFDS you cannot open it on
a system with a version of TurboIMAGE previous to C.10.xx. C.10.xx is
only available on 7.5. Support for jumbo datasets has been available
for a long time, since IMAGE version C.06.xx (shipped with MPE/iX 5.0
PowerPatch 3).

To enable a database for LFDS with Adager you use the command "use
largefiles", available in our 2003 version.

Adager's 2003 release contains support for LFDS as well as a
high-performance function to convert your jumbo datasets to LFDS.
Please contact Adager Support if you are interested in receiving an
early shipment.


Rene

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *