Search

Top 60 Oracle Blogs

Recent comments

linux

Using colplot to visualise performance data

Back in 2011 I wrote a blog post about colplot but at that time focused on running the plot engine backed by a web server. However some people might not want to take this approach, and thinking about security it might not be the best idea in the world anyway. A port that isn’t opened can’t be scanned for vulnerabilities…

So what is colplot anyway? And why this follow-up to a 7 year old post?

Running orachk as part of TFA with support tools bundle

I have previously written a number of posts about OSWatcher integration in Tracefile Analyzer (TFA) w/support tools bundle (available from My Oracle Support Document ID 1513912.1). Thus far I have neglected another useful tool available to administrators in the same package: orachk.

Summary of the environment

My lab system used for this post uses Oracle Restart 12.1.0.2 on top of Oracle Linux 7.4. I installed TFA 18.3 to /opt/tfa. If memory serves me right, TFA isn’t automatically deployed with Oracle Restart 12.1 as it now is with 12.2 and later.

[oracle@server1 ~]$ /opt/tfa/bin/tfactl print version
TFA Version : 18.3.3.0.0

A quick check using tfactl toolstatus reveals that orachk is indeed present:

Oracle wait event ‘TCP Socket (KGAS)’

I was asked some time ago what the Oracle database event ‘TCP socket (KGAS)’ means. This blogpost is a deep dive into what this event times in Oracle database 12.1.0.2.180717.

This event is not normally seen, only when TCP connections are initiated from the database using packages like UTL_TCP, UTL_SMTP and the one used in this article, UTL_HTTP.

A very basic explanation is this event times the time that a database foreground session spends on TCP connection management and communicating over TCP, excluding client and database link (sqlnet) networking. If you trace the system calls, you see that mostly that is working with a (network) socket. Part of the code in the oracle database that is managing that, sits in the kernel code layer kgas, kernel generic (of which I am quite sure, and then my guess:) asynchronous services, which explains the naming of the event.

Little things worth knowing: OSWatcher Analyser Dashboard

I have written a few articles about Tracefile Analyzer (TFA) in the recent past. As you may recall from these posts, a more comprehensive TFA version than the one provided with the installation media is available from My Oracle Support (MOS for short). As part of this version, you get a lot of useful, additional tools, including OSWatcher. I love OSWatcher, simply because it gives me insights that would be very hard to get with sar for example. SAR tends to be the least common denominator on most (proper) operating systems and it’s better than nothing, but please read on and let me explain why I like OSWatcher so much.

Feel free to head back to my earlier posts if you like to get some more details about “stock TFA” and “MOS TFA”. These are terms I coined by the way, you won’t find them in a MOS search.

Repairing a Linux host with disk/filesystem issues

This is a writeup on some scenario’s for disk issues that you could encounter when running linux systems. The linux systems I am talking about are centos/redhat/oracle (EL) version 7 systems. This is just a writeup for myself to know how to deal with different scenario’s, hopefully other people find this interesting too. I don’t believe there is any difference for the below scenario’s and resolutions between running physical/bare metal, virtualised or in the cloud, provided you can get access the you need (like the BIOS POST console). The test configuration uses (legacy) MBR (meaning non UEFI), grub2 as boot loader, LVM for meta devices (you don’t want to run without LVM!!) and XFS for the filesystems.

How to Linux for the SQL DBA Articles on Simple Talk

I’ve started to write a series of articles on Simple Talk from Redgate on Linux for the SQL Server DBA.  Thanks to Kathi Kellenberger, who came to my pre-con in Indianapolis SQL Saturday and then asked if it was something that I’d be up to doing.

The biggest challenge when doing one hour sessions on Linux at SQL Saturdays is that you find out, one hour is just no where, near enough.  The eight hour pre-con we get to dig in deeper, actually work through a number of labs and I feel like students leave with a better grasp on how to work with this new operating system in preparation for managing a database on it.

Installing ZFS on OEL7 UEK4

Here are the commands I use to setup ZFS on Oracle Linux

#This was tested on OEL 7.2 in Oracle Cloud Compute Classic and OEL 7.5 in Oracle Cloud infrastructure
set -x
cat /etc/oracle-release
yum -y install kernel-uek-devel-$(uname -r)
yum install -y yum-utils
yum-config-manager --enable ol7_developer_EPEL
yum install -y dkms
rpm -Uvh http://download.zfsonlinux.org/epel/zfs-release.el7_5.noarch.rpm
sudo yum install -y zfs
dkms status
/sbin/modprobe zfs
systemctl -a | grep zfs
echo "ZFS Pool creation on the last disk added:"
zpool create -f myzpool -m /mnt/myzpool /dev/$(lsblk | awk 'END{print $1}')
zpool status
zpool list

The full blog is on:

Installing ZFS on OEL7 UEK4 for Docker storage - Blog dbi services

Learn Linux With Docker and Microsoft Container Image

I just finished teaching an 8 hour pre-con at SQL Saturday Indianapolis on Essential Linux for the DBA.  The focus of the class was on what the Microsoft DBA would need to know as more SQL Server environments begin to run on Linux.

The obstacles and demands of them will be a bit different than the Oracle crowd, as they may not have the Linux Admin or Unix expertise onsite for support and have to fend for themselves more than I did starting out on Linux.

Some folks asked me why I chose to use Docker with the SQL Server image to teach the class and I wanted to demonstrate why this, over VMWare or other options were my final choice.

RAC One node databases are relocated by opatchauto in 12.2 part 2

In a previous post I shared how I found out that RAC One Node databases are relocated on-line during patching and I promised a few more tests and sharing of implications. If you aren’t familiar with RAC One Node I recommend having a look at the official documentation: The Real Application Clusters Administration and Deployment Guide features it prominently in the introduction. One of the things I like to keep in mind when working with RAC One Node is this, quoting from section 1.3 in said admin and deployment guide:

RAC One node databases are relocated by opatchauto in 12.2 part 1

This is an interesting observation I wanted to share. I have a feeling as if there didn’t seem to be too much information out there for RAC One Node (RON) users, and I hope this helps someone thinking about patching his system.

RAC-rolling patching is well documented in patch readme files, blog posts and official white papers. Most RAC DBAs have a solid handle on the procedure. Patching RAC One Node is a different affair.

What happens when patching a RAC One Node system? As the name suggests a RAC One Node database is a cluster database restricted to one active instance in normal operations. It is possible to relocate the database from one node to another online. Oracle does this by temporarily adding a second instance to the cluster database with the intention of letting it take over from the source instance. At the end of the online relocation, the source instance is shut down, and only the destination instance remains up and running.