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Disk Configuration for retail production machine

Former Member
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hello

i am having V5R4M0DB2SAP retail combination. for production machine i have 18X73 GB hard disk on RAID 5.

i.e total 1080 GB APPROX.

I like to know how much size i should allocate to ASP2 for jour. files.

as my backup policy I am taking online backup daily & off line at weekend.

I am planing ASP1= 980GB, ASP2 =125 GB (2X73) & one hard disk unassigns.

125 GB (2X73) is enough?

kindly suggest best policy. by considering this is Retail system also i have BI & XI in landscape.

Regards

Sachin

Accepted Solutions (1)

Accepted Solutions (1)

Former Member
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Sachin

Please check what type of disk controller you have in your machine? And how many disk controller cards do you have that control all 18 disk units?

If you have the disk controller type with large write cache (700MB or 1.5GB as used in disk controller 2757/2780/571E/571F), then you do not need to create ASP2 to hold journal receivers. In fact, if your SAP system has very high workload, creating ASP2 with too few disk units may produce adverse performance. Using disk controller with large write cache, you can put everything in ASP 1 which will be the simplest configuration that provides the best disk access performance. If you use different disk controller, let me know its type and how many cards (use DSPHDWRSC *AHW command and look for resources whose names begin with DCnn, their types are shown in the next column).

This article should provide you with more information: [Journaling - User ASPs Versus the System ASP|http://www.redbooks.ibm.com/Redbooks.nsf/RedbookAbstracts/tips0602.html?Open]

Also read this thread for more information:

Satid S.

IBM Thailand

Edited by: Satid Singkorapoom on May 8, 2008 2:52 PM

Former Member
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hi Satid

thanks.

DC03 575B-001 Operational Disk Storage Controller.

this is my controller model.

I dont have much idea on this

Thanks /Sachin

Former Member
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Sachin

575B is the auxilliary write cache for 571F disk controller which has 1.5GB write cache and 1.6GB read cache. It is the best disk controller for iSeries internal disks. So, you do not need to create an ASP 2 to keep the journal receivers.

Answers (1)

Answers (1)

Former Member
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Hi Sachin

I would think 125 GB should be enough for it, allthough a lot will depend on how long you want to keep the journals on the system, once the backup has been taken.

Having a different ASP is good, but probably in these days of fast disk arm controllers with cache, putting journals in separate ASP doesn't achive a lot. Believe the old reason for doing it was to get away from the the IO bottleneck. But still is a good practice. I would say make ASP 2 Fully mirrored intstaed of RAID 5.

Are you deleting the journals manually everyday ? Out of my experience I have seen BI generating a lot of journals, because of the massive deletes/recreates etc everyday( upto 100 GB in a day).

Are all these systems on the same LPAR(or BOX) or different LPARs?

Thanks

Abhi