linux

I just did an update from Oracle Linux 5.7 to 5.8 on one of my VirtualBox RAC installations and things are not looking to clever at the moment. After a reboot, the ASM instances and therefore the database instances wouldn’t restart. A quick look showed the ASM disks were not visible. On this installation I was using UDEV, rather than ASMLib. In checking the UDEV rules I noticed the scsi_id command on OL5.8 doesn’t report an ID for partitions on disks, only the disks themselves. For example, on OL5.7 I get this,

# /sbin/scsi_id -g -u -s /block/sdb/sdb1
SATA_VBOX_HARDDISK_VBd306dbe0-df3367e3_
#

On OL5.8 I get this,

# /sbin/scsi_id -g -u -s /block/sdb/sdb1
#

If I run it against the disk, rather than the partition it works fine.

I put a few more Linux articles live yesterday.

I am proud to be able to speak at the first instalment of the Availability, infrastructure and management SIG on March 14th in  the London City office.

The event is announced on the UKOUG website here:

http://www.ukoug.org/events/ukoug-availability-infrastructure-and-management-sig-meeting/

Unfortunately I will be between you and lunch! I hope that works out, and I don’t overrun.

I’ve been involved in a number of blog comment, email and twitter exchanges over the last few months about the 11gR2 on RHEL6/OL6 certification issue.

The last time I blogged specifically about it was in October and it’s now over 6 months since Red Hat completed their part in the certification of 11gR2 on RHEL6, yet still no news.

I wrote in my New Years Resolutions post I was considering writing some revision notes for, and ultimately sitting, the RHCSA and RHCE exams.

I’ve started on that journey now with a bunch of articles.

I have set up my new lab server yesterday, which in essence is a rack mounted server with a core i7 2600 processor, 32GB RAM and 3 TB of (slow) disk. When I moved some of my VMs across from an identical system (except that it was a core i7 920) and tried to start the domU, it repeatedly crashed. The message from the console was a simple question: is xend running?

I couldn’t believe my eyes-using identical software now produced segmentation faults? How is that possible. I am using xen 4.2, kernel 3.1.9-1.4-xen and libvirt libvirt-0.9.6-3.3.1.x86_64

I started the troubleshooting with the xen logs. There was no output in the debug log, however the xend.log showed these lines:

It is human nature to draw from experiences to make sense of our surroundings.  This holds true in life and performance tuning.   A veteran systems administrator will typically tune a system different from an Oracle DBA.  This is fine, but often what is obvious to one, is not to the other.  It is sometimes necessary to take a step back to tune from another perspective.

I recently have ran across a few cases where a customer was tuning “Sorts” in the database by adding memory. Regardless of your prospective, every one knows memory is faster than disk; and the goal of any good tuner is to use as much in memory as possible.   So, when it was noticed by the systems administrator that the “TEMP” disks for Oracle were doing a tremendous amount of IO,  the answer was obvious right?

One of the tasks I am performing quite regularly is to deploy Oracle software in form of an RPM. In a previous post I described how this proces could work, based on a post by Frits Hoogland.

Employing the same method, I ran into problems with Oracle 11.2.0.x clients. A few facts to start with:

• Oracle 11.2.0.3 client 64bit
• Golden image created on Oracel Linux 5
• Destination: SuSE Enterprise 10 SP4

The problem described here is most likely applicable to other Oracle clients as well although I haven’t verified that.

The problem

While I was performing a three day seminar recently in Switzerland I came across this new option in cluvfy.

Normally you’d run cluvfy in preparation of the installation of Grid Infrastructure or a set of RAC binaries to ensure everything is ready for the next step in the RAC install process. Beginning with 11.2.0.3, there is another option that’s been sneaked in without too much advertisement: the healthcheck.

Part of the “comp” checks, it takes the following options:

cluvfy comp healthcheck [-collect {cluster|database}] [-db db_unique_name] [-bestpractice|-mandatory] [-deviations] [-html] [-save [-savedir directory_path]

The most extensive report is run without any options, as shown in the appendix (the output is too long to display at this stage of the post) You have the following options:

Before I joined Blue Gecko, I did independent remote DBA work, and called myself ORA-600 Consulting. Stemming from my hair-raising experiences in the trenches at Amazon in the late ’90s / early 2000s, I decided to specialize in emergency DBA work for companies in the midst of crises (I know, great idea for someone who wanted to get away from the Amazon craziness, right?).

One day in 2009, a company in Florida called my cell phone at 2AM. They described their problem as follows: