Pythian Group

We have a client that runs an application that, for whatever reasons, does NOT like daylight saving time. For that reason, the Oracle server is kept in Eastern Standard Time and does not change with the rest of the eastern United States when DST begins and ends every year. They accomplish this with a custom /etc/localtime file. However, they left /etc/sysconfig/clock set to “TZ=America/New_York,” which would prove fateful as I shall point out. So, with the custom localtime file, the “date” command as well as selecting sysdate or systimestamp would always return the current time in Eastern Standard Time. When it is Daylight Saving Time, as it is right now, this would be one hour behind “real” time as we consider it.
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In looking at this subject, most of you will say: Hey Yury! What’s new that you can tell us about? The following note describes it all:
11gR2 Grid Infrastructure Does not Use ULIMIT Setting Appropriately [ID 983715.1]

These were exactly my thoughts when I was called to troubleshoot a case where a DB instance, starting with the “srvctl start instance” command failed to use Huge Pages in Linux.

It appears that it isn’t that obvious what exactly you should configure to make sure that your Oracle Instances uses Huge Pages memory regions for shared memory. The tricky area is the /etc/security/limits.conf file.
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It started out innocently enough: Two node RAC cluster on two Linux RHEL5 with Netapp NFS used as shared filesystem for all shared files. My favorite OS and storage, so I felt confident that clusterware installation will be as smooth as it usually is. I told the customer that this can be done in 3 hours.

What I didn’t take into account is that this was my first 11gR2 installation, and that much have changed since 11gR1. As things turned out, it took over 20 hours of my time and a lot of help from colleagues and even former colleagues before we had a successful installation.

The time it takes you to read this blog post (and any other on this subject) is likely to be time well spent.

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Upgrading to 11g Release Grid Infrastructure? You probably want to read on…

Oracle 11g Release 2 Grid Infrastructure has been dramatically redesigned compare to 10g and 11gR1 Clusterware. Coming with impressive set of new features, Grid Infrastructure also uses much more memory. While RAM is rather inexpensive these days, it does pose an inconvenience in some scenarios. Particularly, for sand-box type installations that I use all the time for my own tests and demonstrations. For production upgrades, you need to be aware of and plan for increased memory usage.

I’ve been able to easily run a 2 node 10g RAC cluster on my MacBook with 4 GB of RAM allocating less than 1 GB of RAM to each virtual machine. That was even enough for a mini database instance with a very small memory footprint. Oracle 11g Release 1 was pretty much the same except maybe the database instance itself required a bit more memory but one node could still fit within 1 GB of RAM.

In 11gR2, bare-bone Grid Infrastructure processes alone consume 10+ times more memory (11.2.0.1 on 32 bit Linux to be precise): Read the rest of this entry . . .