linux

Just a quick note about the Call for Papers for the upcoming UKOUG 2012 annual conference to be held on 3rd to 5th December in Birmingham. I have been a speaker for the last 5 years and I think this is a very valuable conference about Oracle technology in Europe. If you want to be […]

I’ve been using the beta versions of UltraEdit 3.1 for Mac and Linux for a while, but I only noticed today the production version has been released. I normally get email  updates, so I figure this one must have got directed to spam by accident.

Anyway, I’m now rockin’ the latest version on both platforms. Happy days…

Cheers

Tim…

This is as much a note to myself how to do this in the future as it is something hopefully worth reading for you. The requirement has been precise as always: migrate a database from 10.2 on SPARC to 11.2 on Linux. In the process, go from Veritas to ASM and make it quick!

I like short briefings but this was too short. Since the database was reasonably large I opted for the transportable tablespace approach, however I now think that a massively parallel impdp with network_link could have saved me quite a bit of time.

The following is by no means  the complete story, but hopefully gives you an idea how to do these things. Always check, and document, then test (rinse and repeat). Only when proper signoff is received should you try such a process in production. Remember to script it and have at least one clean run of the scripts! This process is not super-quick, if you have low downtime requirements then consider Streams or better: Golden Gate for the process.

In part 1 we performed a series of experiments to explore the relation between CPU utilization and Linux load average. We came to the conclusion that CPU utilization clearly influences the load average. In part 2 we will continue our experiments and take a look if disk I/O also influences the Linux load average. Disk […]

Following on from my post on AntiVirus Software and Apple Macs, I decided to add antivirus to my desktop machines also. I chose ClamAV because it is part of the Fedora repository. I wrote a quick note about installing ClamAV on Fedora and Enterprise Linux (RHEL, Oracle Linux, CentOS etc.).

• Linux Antivirus (clamav, freshclam, clamscan, clamtk)

Not surprisingly, scans revealed no viruses on any of my Fedora machines.

Cheers

Tim…

A few twitter posts have already indicated that I have a new machine in my study-a Supermicro server with the H8DGi6-F motherboard, 2 12-core AMD 6238 processors and 32 GB RAM. And since I have been given a vSphere 5 Enterprise Plus license, what better to test than this combination! I have to say the installation of ESX5i is very straight forward: get the ISO image, burn it, install it. Done-and ESX5i has support for the AMD 6200 processors built in, which suffer from L1 cache invalidations in certain situations.

I have to say that ESX5i is a data center product: I haven’t been able to attach a USB hard disk to it in order to copy my ISO images. Apparently there is a way for ESX 5i (and 4i) to mount vfat formatted USB disks to automatically mount the devices as “NO NAME” but I haven’t been able to get this to work.

I have been playing around with Fedora 17 beta in preparation for my server upgrades when it is released at the end of the month. While I was at it, I did my typical articles for Fedora.

• Fedora 17 (F17) Installation
• Oracle Database 11g Release 2 (11.2) Installation On Fedora 17 (F17)

I’ll run through them again when the final release drops, then officially put them live.

Cheers

Tim…

Last month I wrote about a problem I saw with scsi_id and UDEV in  OL5.8. As it screwed up all my UDEV rules is was a pretty important issue for me. It turned out this was due to a mainline security fix (CVE-2011-4127) affecting the latest kernels of both RHEL/OL5 and RHEL/OL6. The comments on the previous post show a couple of workarounds.

Over the weekend I started to update a couple of articles that mentioned UDEV rules (here and here) and noticed the problem had dissapeared. I updated two VMs (OL5.8 and OL6.2) with the latest changes, including the UEK updates and ran the tests again and here’s what I got.

In preparation for a research project and potential UKOUG conference papers I am researching the effect of NUMA on x86 systems.

NUMA is one of the key features to understand in modern computer organisation, and I recommend reading “Computer Architecture, Fifth Edition: A Quantitative Approach” from Hennessy and Patterson (make sure you grab the 5th edition). Read the chapter about cache optimisation and also the appendix about the memory hierarchy!

Now why should you know NUMA? First of all there is an increasing number of multi-socket systems. AMD has pioneered the move to a lot of cores, but Intel is not far behind. Although AMD is currently leading in the number of cores (“modules”) on a die, Intel doesn’t need to: the Sandy-Bridge EP processors are way more powerful on a one-to-one comparison than anything AMD has at the moment.

May 4th: some updates after discussion with Jeff Holt, Cary Millsap and Ron Christo of Method-R.

There’s all the documentation, and there all the terrific blogs about performance and Oracle wait events. But if you more or less start with this stuff, or encounter a wait event that is not (extensive enough) documented, or an event turns up and gives a response time you don’t expect, you need to understand what that wait event means. If you don’t know, it’s easy to get stuck at this point.

If you are familiar with waits, and just want to dig further, progress to “Get to know wait events”, if you want to get up speed with waits, read on.

What is a wait event?

This is the definition of the performance tuning guide in the Oracle documentation: