Pythian Group

I’ve started putting together some information about the Oracle Database Appliance in question-and-answer form. If you have an unanswered question, ask away in the comment section below.

(Update: Oracle has come out with their official FAQ as well)
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No, this isn’t a re-post of my earlier blog about bug 1233183.1. We’ve found a fun new bug that seems to be specific to our poor standalone ASM instances when upgrading from Oracle Grid Infrastructure 11.2.0.1 to 11.2.0.2.

The bug was first brought to my attention about four days after completing the Grid Infrastructure upgrade. The client system administrator (SA) noticed that the disk holding the Oracle home directories was slowly filling, at the rate of about 1Gb per day. We identifed that core dump files being created under the new GRID_HOME/log//diskmon/ directory, at the rate of about 1 every 10 minutes, each one about 8M in size. That adds up to 1152M (or just over 1Gb) per 24-hour day. Add that to the 8Gb that was being held in GRID_HOME/.patch_storage (we had to rollback the 11.2.0.1 April 2010 PSU and apply the 11.2.0.1 July 2010 PSU just to upgrade to 11.2.0.2), and that put a bit of a squeeze on the free disk.

The good ol’ OTN forums led me to bug 10283819. The original poster there shared also that removing the old (11.2.0.1) grid home directory and restarting diskmon services stopped the core dump creation. The poster then went to question a second issue with increased diskmon.log writing. After a solution was found for that, Oracle Support closed the bug for some reason, without ever addressing the core dump creation.

I can verify that removing the old 11.2.0.1 grid home (I did a tar+bz2 first) and restarting the services did stop the core dump creation, and am pushing back to Oracle support to get the bug re-opened or a new bug filed to specifically address this. In the meantime, if you are unable or unsure about removing the old grid infrastructure home, it should be safe to have a regularly scheduled script remove the diskmon core dump directories and save you a full disk surprise late some night.

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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One of the exclusive Exadata features is the Smart Flash Cache (Oracle White Paper PDF). On a full rack, there is 5 TB of flash cache, which can store a significant amount of data. Quite often it’s several times more than the working set for a given reporting system.
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I’ve just published Oracle Database 11g Express Edition Amazon EC2 image (AMI) but most of you have never used Amazon EC2… Not until now! This is a guide to walk you thorough the process of getting your very first EC2 instance up and running. Buckle up — it’s going to be awesome!

1. Go to Amazon Web Services and open an account. You could use one that you buy your books with.
2. Go to AWS Management Console for EC2 and sign up for Amazon EC2. You will need your credit card for this. You will not be charged anything unless you are either start using EC2 instances or allocate EBS storage and other related items. The sign-up page shows you all the pricing. You will especially like “Free tier for new AWS customers” section that gives you 750 hours of Micro instance uptime, 10 GB of EBS storage some bandwidth and few small goodies. This mean that you will not be charged anything in the beginning of your experiments. They will also do phone verification — I can’t remember I’ve seen it last time so it must be reasonable new. Works for cell phones too. Activation usually takes just few minutes and you’ll get an email confirmation and you get access to EC2, VPC, S3 and SNS. Direct link to AWS Management Console for EC2
3. Now you can launch your first instance. So let’s start Oracle 11g XE beta image that I published just recently. Click “Launch Instance” then select “Community AMIs” tab. It will start loading AMIs list and it will take ages so don’t wait for it to finish and search for “pythian” – you will get pythian-oel-5.6-64bit-Oracle11gXE-beta image with AMI ID ami-e231cc8b the latest at the time of this writing.
   
   Select that image.

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Update 23-Feb-2012: I have removed this image because (1) it’s outdated and based on 11g XE beta while released version is there and (2) licensing agreement doesn’t permit redistribution of software.

That’s right folks! Playing with latest beta of free Oracle Database 11g Express Edition couldn’t be any easier than that. If you are using Amazon EC2, you can have a fully working image with 64 bit Oracle Linux and Oracle 11g XE database running in a matter of few clicks and a minute to get the instance to boot.

Image — ami-ae37c8c7
Name — pythian-oel-5.6-64bit-Oracle11gXE-beta-v4
Source — 040959880140/pythian-oel-5.6-64bit-Oracle11gXE-beta-v4

You can find it in public images and at this point it’s only in US East region.

If you never used Amazon EC2 before, see detailed step-by-step guide on how to get started with EC2 on the example of this 11g XE image.

This image works great with Amazon EC2 Micro instance and I configured it specifically for Micro instance. Micro instance costs you only 2 cents per hour to run or even less than 1 cent if you are using spot instance requests (and there is free offer for new AWS users as Niall mentioned in the comments).

So what’s there?

• Oracle Enterprise Linux 5.6 64 bit (I started with 5.5 and updated to the latest)
• Oracle Database 11g XE Beta (oracle-xe-11.2.0-0.5.x86_64)
• Database created and configured to start on boot
• APEX coming with 11g XE configured on port 8080 and remote access enabled
• 10GB root volume on EBS with 5+GB free for user data. You could store up to 11GB of data in 11g XE and there is a way to grow volumes if you need but for more critical use then playground, I’d allocate separate EBS volumes anyway.

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Greg Rahn of Oracle’s real-world performance group posted a technical review of an article I wrote last summer, entitled Making the Most of Oracle Exadata. I have a few comments on the technical concerns Greg raised.
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The past four days have found me very frustrated and at wits’ end while testing upgrades of standalone Oracle Grid Infrastructure (ASM) 11.2.0.1 to 11.2.0.2 on RHEL/OEL 5 VMs. The upgrade would seem to go fine, but after rebooting, I would see ASM and LISTENER running under the old (11.2.0.1) grid home directories again.

Looking at /etc/oratab, I saw this:

$ grep -i asm /etc/oratab
+ASM:/u01/app/grid/product/11.2.0/grid_1:N              # line added by Agent

grid_1 is the old grid home, I expect to see grid_2. The comment about being added by Agent led me to a path where I eventually took a look at /etc/init.d/ohasd, which is basically the master script that starts everything up. I noticed that this file hadn’t been updated as part of the patching, and contained this:

$ grep -i crs_home /etc/init.d/ohasd
ORA_CRS_HOME=/u01/app/grid/product/11.2.0/grid_1
export ORA_CRS_HOME

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For those of you in the New York City area, I’ll be speaking at the NYOUG joint BI/DW and Web SIG meeting. The topic will be a case study of Pythian’s Exadata implementation at LinkShare. It will be 6pm this Thursday, December 2, at the APRESS offices at 233 Spring Street, sixth floor. Previous notices did say fifth floor, but I can confirm it will indeed be the on the sixth. It’s free for NYOUG members and $10 for non-members. The NYOUG would like confirmations by November 30 to get an idea of numbers and how much pizza to order, so drop them a line at info@nyoug.org if you plan on attending.

Further info from the NYOUG website

If you can’t make it, recordings of my webinar on the same topic are available online as well.

The Oracle Enterprise Manager Grid Control monitoring plug-ins for Exadata have been released. This is great news for Exadata users, since important components like InfiniBand switches previously had no direct monitoring. The plug-in bundle includes five separate monitoring plugins:
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