Re: Commitment Control Overhead

[John Earl <johnearl@xxxxxxxxxx>]

Al Barsa, Jr. wrote:

> At 04:56 PM 3/9/98 -0600, you wrote:
> >Can someone steer me in the direction of statistics about using Commitment
> Control.  I have only found the Advanced Backup and Recovery text talking
> about CC, so far.

<snip>

> First of all, commitment control requires journaling.  The overhead of
> journaling is about 5%, assuming the journal receiver is in a separate ASP
> that has not overflowed.  The new 'remote journaling' support in V4R2 is
> about 14%.

5% ?? Wow! I'm surprised it's so high.  Would that be 5% of CPU usage or 5% of
average I/O time attributted to a job?

I would have expected that journalling with commitment control to a separate ASP
(where your head movement is going to be next to nil) would be almost
imperceptable.  Do many people see this large an impact?

jte

--
John Earl Lighthouse Software Inc.
8514 71st NW Gig Harbor, WA 98335
253-858-7388 johnearl@lns400.com

Without Lighthouse Network Security/400, your AS/400 is wide open.
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