This blog contains experience gained over the years of implementing (and de-implementing) large scale IT applications/software.


There are various methods of tuning an SAP system, but sometimes the operating system vendor will permit specific tuning so that the SAP system can take better advantage of the available resources.
Usually, you can find whitpapers on the O/S or hardware vendor’s web site, but also SAP will themselves develop a range of SAP notes that will offer avice and guidance when running on certain approved hardware partners.
If you’re using HP-UX 11iv3 (11.31) and you are running SAP, then here are some gems direct from SAP themselves:

172747 HP-UX OS Parameter Recommendations
798194 HP-UX async IO trace files
837670 HP-UX OS Patch Requirements
918279 HP-UX SAPOSCOL Versions
1077887 HP-UX filesystem options
1329878 Using non-default pagesize on HP-UX
1351051 Support of Oracle on HPVM
1457063 HP-UX Consolidating SAP Systems
1575609 Future HP-UX support for SAP on Oracle

I would highly recommend the OS Parameters note.
If you’re suffering I/O performance issues, make sure that you have set the correct block size as per 1077887.
A huge (>10%) reduction in memory usage can be obtained following 1329878, but only if you are using Oracle 11g.

Using the direct I/O option alone on a VxFS 5.0 environment decreased Data Protector backup times by over 1 quarter e.g. a 1.5 hour backup reduced to ~1 hour.

I haven’t investigated the HPUX_SCHED_NOAGE O/S parameter option yet (I need the audacity to recommend it to the server team!), but according to this excellent blog post by Christian Bilien, it should help your environment significantly if you’re running more than one Oracle database on a SMP system.
My reasoning is that there will be more than one CPU hungry Oracle thread and they could each be battling against each other (ageing each other out) even more so in a well tuned system with less I/O (large SGA/PGA and well tuned SQL) meaning less voluntary context switches and more forced ones. It’s possible that in this situation, without HPUX_SCHED_NOAGE, you could start to see CPU bottlenecks.

HP also produce their own performance recommendations for running Oracle.
Here’s one on the HP recommended filesystem IO options.
Notice that it says if you’re using VxFS v5.0, you don’t need to worry about 1KB block sizes on Redo and Archive Log partitions.

WARNING: Take heed in the warning about Progress databases on file system partitions with directio enabled on the mount options.  I have personally experienced issues where Progress applications have had a 20x decrease in performance!  It’s a fact, Progress is not very good without the file system cache.

This one is specific to tuning HP-UX TCP/IP.  Very useful if you’re seeing networking bandwidth problems in you environment.

Finally, the HP-UX Performance Cookbook provides an excellent source of information.
I have noticed that some of the SAP Oracle recommended parameters (830576 “Parameter Recommendations for Oracle 10g”) are specific to HP-UX, I have found that a good set of descriptions for some of these are covered in this HP Oracle paper: The Oracle Database on HP Integrity servers.

It’s really a trade off between what SAP say and what Oracle say.
Obviously Oracle know there own database system, so anything Oracle says can also be included.
I generally follow the top down rule, where SAP overrides anything that is contradictory from HP or Oracle, Oracle overrides anything contradictory from HP, and I only implement any parameters from HP if neither Oracle or SAP have anything to say on the matter:
– HP (OS)
 – Oracle (RDBMS)
  – SAP

Running Oracle (Windows vs UNIX/Linux)

For most of my IT career I’ve been using UNIX/Linux (let’s call this ULix to save my fingers) to run Oracle.
Humans are creatures of habit (like cats and so why would I want to change this.
Running Oracle on ULix is a measured quantity.  It works, it’s reliable, you can tune it and then you can really tune it.

Whilst browsing my book library I came across a book I’ve had for years:
Configuring & Tuning Databases on the Solaris Platform” by Allan N. Packer
If you have ever wondered what the possibilities are in tuning an Oracle system on ULix, then read this book.  It might be old, but it’s a good one, and it establishes all the basic principles of tuning.

Now if we were to consider running Oracle on Windows (, then out-of-the-box ( it would work perfectly fine.

Microsoft have made vast improvements to the monitoring/tuning capabilities in newer Windows Server versions, but I don’t think this can compare to the flexibility of monitoring/tuning in ULix.
I find it very difficult to profile a database on Windows.
Think about it, where can I see the individual shadow processes ( at the OS level?

On Tanel Poder’s company’s website, there’s a great whitepaper “Understanding LGWR, Log File Sync Waits and Commit Performance”.
In this whitepaper, Tanel mentions monitoring and tuning the Oracle log writer (LGWR) process to get better CPU time.  I thought to myself, how would someone do this on Windows?

I really don’t think you can.
To summarise: I like Windows, it can run Oracle RDBMS perfectly fine, but it’s not as flexible as running on ULix.