Performing in the cloud – network latency

To me, ‘cloud computing’ is renting a compute resource to perform a task. In order to use that compute resource, you need to instruct it to do something, which is typically done via the network. If the task the compute resource needs to fulfil is being an application server or being a client or both in the case of an application server that uses an Oracle database, the network latency between the client of the (more...)

Oracle Linux Update from 7.2 to 7.3 crashes with uncorrectable CPU error

During the Upgrade of Oracle Linux 7.2 to 7.3 with “yum update”, when updating the microcode_ctl package, the system crashed and firmware reported an uncorrectable CPU error after reboot.

It turned out that the update of the package in combination with specific Intel CPUs causes the issue. In the meantime, there is a red hat bug and solution available.

 

References:

  • https://community.oracle.com/thread/3997160
  • https://bugzilla.redhat.com/show_bug.cgi?id=1398698
  • MOS: The system could (more...)

ORA-00322: log 41 of thread 2 is not current copy

On a Data Guard Physical Standby, I noticed the following in the alert log:

Fri Jan 13 08:12:39 2017 
Errors in file /u01/app/oracle/diag/rdbms/v1s/V1S1/trace/V1S1_arc1_399861.trc: 
ORA-00322: log 41 of thread 2 is not current copy 
ORA-00312: online log 41 thread 2: '+RECOC1/V1S/ONLINELOG/group_41.3099.912775569' 
ORA-00322: log 41 of thread 2 is not current copy 
ORA-00312: online log 41 thread 2: '+DATAC1/V1S/ONLINELOG/group_41.807.912775567'

If you read metalink note:

Physical standby – alert*log shows ORA-322, ORA-312 intermittently (more...)

ORA-00314: log 42 of thread 2, expected sequence# 37363 doesn’t match 37361

On a Data Guard Physical Standby, I noticed the following in the alert log:

Mon Jan 30 12:37:22 2017
Errors in file /u01/app/oracle/diag/rdbms/v1s/V1S1/trace/V1S1_arc1_105040.trc:
ORA-00314: log 42 of thread 2, expected sequence# 37363 doesn't match 37361
ORA-00312: online log 42 thread 2: '+RECOC1/V1S/ONLINELOG/group_42.15446.927996415'
ORA-00314: log 42 of thread 2, expected sequence# 37363 doesn't match 37361
ORA-00312: online log 42 thread 2: '+DATAC1/V1S/ONLINELOG/group_42.1051.927996411'

If you read metalink note:

ORA-00314: LOG 404 OF (more...)

An introduction to Performance Co Pilot, part 2.

This second blogpost on Performance Co Pilot or PCP in short is about visualisation. In case you haven’t read the first part, here it is, which describes how it works, why you should use it, and how you can install it.

Pmchart.
One way of visualising PCP is using the pmchart utility. The pmchart utility is installed via the pcp-gui package (yum install pcp-gui). The pmchart utility uses X to display a window and (more...)

Oracle Database Backup Service Fails with: ORA-19511: – KBHS-00715: HTTP error occurred ‘oracle-error’

I discovered a Oracle Cloud Database Backup failing with:

Starting backup at 2017/01/20 20:00:04
current log archived
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup plus archivelog command at 01/20/2017 20:00:08
ORA-19554: error allocating device, device type: SBT_TAPE, device name:
ORA-27023: skgfqsbi: media manager protocol error
ORA-19511: non RMAN, but media manager or vendor specific failure, error text:
 KBHS-00715: HTTP error occurred 'oracle-error'
KBHS-00712: ORA-28750 received from local  (more...)

Creating a RAC 12.1 Data Guard Physical Standby environment (3)

In the previous two parts of this series you read about my lab environment and the preparations on the network side as well as the database. In this part I’ll cover the database duplication. Again, this won’t be a short post …

NOTE: As always, this is just a demonstration using VMs in my lab, based on my notes. Your system is most likely different, so in real-life you might take a different approach. The techniques (more...)

Auditing Oracle database stopping and starting using the ELK stack

This blog post is about two things: one how you can monitor who is bringing you database up and down (there is a twist at the end!) and two how you can very conveniently do that with aggregated logs in a browser with a tool called ‘Kibana’, which is the K in ELK.

What is the ‘ELK stack’?
The ELK stack gets it’s name from Elasticsearch, Logstash and Kibana.
– Elasticsearch is an open (more...)

I’m speaking at Advanced Spark Meetup & attending Deep Learning Workshop in San Francisco

In case you are interested in the “New World” and happen to be in Bay Area this week (19 & 21 Jan 2017), there are two interesting events that you might want to attend (I’ll speak at one and attend the other):

Advanced Spark and TensorFlow Meetup

I’m speaking at the advanced Apache Spark meetup and showing different ways for profiling applications with the main focus on CPU efficiency. This is a free Meetup in San Francisco hosted (more...)

Ubuntu: Hibernate/Suspend to disk: Resume problem with ATI Radeon R7

On a new Lenovo laptop i had some issues with supsend/resume.
I installed tux on ice and the suspend process worked, but the resume just freezed after some seconds.

First step to solve this problem was to stop the graphics (/etc/init.d/lightdm stop) and try it again.

This attempt worked without a problem, so it was clear: the resume problem is a issue with the graphic card:
laptop:~$ lspci
[...]
01:00.0 Display controller: (more...)

Using Linux Screen to protect against network breaks

When I carried out my first Exadata patching, I came across ‘Linux Screen‘ in the documentation, which Oracle recommended to use when patching:

“It’s recommended to run the dbnodeupdate.sh session using the Linux ‘screen’ or ‘vnc’ utility such that when a network problem breaks the connection to the server the patching session continues.”

Basically ‘Linux Screen‘ allows you to:

  1. Have a shell that can be reconnected to if you (more...)

Creating a RAC cluster using Ansible (part 2)

In my previous 2 blogposts i explained how to setup a Vagrantfile that deploys 2 virtualbox machines that can be used as a basis for a RAC cluster and how you could use Ansible to deploy RAC on those VM’s. In this post i want to dive a bit deeper into how i setup Ansible and why, keep in mind that this just one way of doing this.

The Github repository containing all the files (more...)

Virtual Development Server: Install Jenkins for Continuos Integration / Delivery / Deployment

jenkins

For automation of all of my processes I need Jenkins in my development server.

First I had installed Jenkins as Docker container via Vagrant Docker provider. But with this architecture it was very complicated to create docker images and run Docker containers on the Docker host, in this case my Vagrant Virtualbox.

So for simplification I have decided to install Jenkins with the provisioning of the Vagrant Virtualbox via a shell provider in my Vagrantfile:

...
   (more...)

Ubuntu: WLAN module for bcm43-chipset gone after reboot…

Today i ran with a laptop into the following problem:
After a reboot the system lost its WLAN:
 # uname -a Linux Notebook 3.13.0-86-generic #131-Ubuntu SMP Thu May 12 23:33:13 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
and
# lspci | grep 802.11
02:00.0 Network controller: Broadcom Corporation BCM43142 802.11b/g/n (rev 01)
Trying a modprobe wl failed...
There were some posts, which suggested to install kernel-drivers, dkms and so on, but (more...)

Debian dist-upgrade: from 7(wheezy) to 8(jessie): udev…

I was running my own kernel on my laptop. But doing the upgrade from debian 7 to 8, i ran in the following problem:
Since release 198, udev requires support for the following features in
the running kernel:

- inotify(2)            (CONFIG_INOTIFY_USER)
- signalfd(2)           (CONFIG_SIGNALFD)
- accept4(2)
- open_by_handle_at(2)  (CONFIG_FHANDLE)
- timerfd_create(2)     (CONFIG_TIMERFD)
- epoll_create(2)       (CONFIG_EPOLL)
Since release 176, udev requires support for the following features in
the running kernel:

- devtmpfs         (CONFIG_DEVTMPFS)

Please upgrade your (more...)

Debian dist-upgrade: Laptop suspends 30s after boot / startup

After i moved to jessie (Debian 8) my laptop moved to suspend to RAM about half a minute after startup.
There was no message in the logfiles and even worse the resume does not work at all...
The configuration for the suspend was in here:
/etc/systemd/logind.conf:
 [Login]
#NAutoVTs=6
#ReserveVT=6
#KillUserProcesses=no
#KillOnlyUsers=
#KillExcludeUsers=root
#InhibitDelayMaxSec=5
#HandlePowerKey=poweroff
HandleSuspendKey=ignore
#HandleHibernateKey=hibernate
HandleLidSwitch=ignore
#PowerKeyIgnoreInhibited=no
#SuspendKeyIgnoreInhibited=no
#HibernateKeyIgnoreInhibited=no
#LidSwitchIgnoreInhibited=yes
#IdleAction=ignore
#IdleActionSec=30min
#RuntimeDirectorySize=10%
#RemoveIPC=yes
After changing the lines "HandleLidSwitch" and "HandleSuspendKey" to ignore (more...)

Debian dist-upgrade: ipw2200 firmwares missing…

After the dist-upgrade the ipw2200 wireless chipset drivers are missing.
Grrrr...
No more internet access - so i had to use a good old LAN cable ;-)

The fix was very easy:
apt-get install firmware-ipw22x00
rmmod ipw2200
modprobe ipw2200
 and the wireless network is up again...

Debian dist-upgrade 5 (lenny) to 6 (squeeze): insserv: exiting now

After several years i decided to upgrade my old laptop to the current debian version.
The first
apt-get dist-upgrade
ran into the following problem:
insserv: warning: script 'K01hotplug-net' missing LSB tags and overrides
insserv: warning: script 'K01x2goserver' missing LSB tags and overrides
insserv: warning: script 'K01oracle-xe' missing LSB tags and overrides
insserv: warning: script 'S85vpnagentd_init' missing LSB tags and overrides
insserv: warning: script 'S02vpnclient_init' missing LSB tags and overrides
insserv: warning: script 'S15initrd-tools.sh' missing (more...)

Problems with big SGAs (>200G) on Linux

I recently had an issue where a database with 240GB SGA (1 huge shared memory segment) configured with hugepages on a system with 512G RAM was suddenly becoming instable and new logons were denied with these error message:


ORA-01034: ORACLE not available
ORA-27123: unable to attach to shared memory segment
Linux-x86_64 Error: 22: Invalid argument
Additional information: 2667
Additional information: 1736718
Additional information: 215016800256

This was strange because ipcs -a showed all shared memory segments (more...)

Install cx_Oracle for Python

This shows you how to install the cx_Oracle library for Python 2.7 on Fedora Linux. If Fedora has it on the server you can download it with the following yum command:

yum install -y cx_Oracle-5.2.1-11g-py27-1.x86_64.rpm

Currently, you’ll get the following failure because it’s not available in the Fedora repository:

Loaded plugins: langpacks, refresh-packagekit
mysql-connectors-community                                      | 2.5 kB  00:00:00     
mysql-tools-community                                           | 2.5 kB  00:00:00     
mysql56-community                                               | 2.5  (more...)