Re: Journal ASPs

[Lo <raikovl1@xxxxxxxxxxxxxxxx>]

Gordon Searles wrote:

> We have 4 AS/400s with 30 - 120 GB of RAIDed DASD on each.  2 of the 4
>
> systems have journal ASPs.  Ideally we would like to have all 4
> systems
> the same.  IBM used to recommend a seperate user ASP for journalling
> for     performance and protection.  Now with RAID they seem to be
> saying
> that the benefits are no longer there, is that true?

GordonIn my experience RAID has very little to do with a need of
separate ASP for journalling. This separate ASP is primarily required
for the disk head movements reduction while doing journalling and is
extremely important if the update volumes to your DB are high. Of
course, it's not the best of examples, but I witnessed a certain batch
process running 2 times slower (2 hours instead of 1 hour) for this
particular reason. But the number of DB updates in my case was extremely
high (somewhere around 2 million). It was AS/400 model 530 with 80 GB
disk space.

Lo



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