linux

oraclebase's picture

Tomcat, Oracle Linux and VMware

Following from yesterday’s post about Cloud Control 12cR3, Oracle Linux and VMware, I thought I would just mention something I put live yesterday evening.

We have a 3rd party Java-based application that runs on Tomcat 7 and Java 7 that until recently was running on RHEL5 on physical hardware. It runs against an Oracle database, but that is not housed on this server. This application is not that big, but it is *very* high profile as it is what we use to process our REF submissions. If you know anything about higher education in the UK, you’ll know that REF is a very big deal, especially as we are within a couple of months of the next submission.

oraclebase's picture

Cloud Control 12cR3, Oracle Linux and VMware

I mentioned some time ago that I was pushing my current company to move much of their gear on to VMware, mostly because of poor resource utilization on many of the servers. That process is still under way.

One thing I wanted to mention specifically was our use of Cloud Control 12cR3. Up until recently, we were using physical kit for this. We had an 11.2 database on HP-UX, With HA provided by HP Service Guard. We had two management servers on physical kit running RHEL5 pointing at this Service Guard package to give us some resiliency in of the OMS. It worked, but it was over complicated and I was never really happy with it for a number of reasons:

martin.bach's picture

Clusterware and listener management gotcha in 11.2

I have come across an interesting situation recently and thought it was worth blogging about. My friend Doug Burns might like it, it has to do with consolidation.

Background

I have seen quite a few sites in my career where the separation (of duties/listeners/disk space/log destinations) was paramount-and for good reason! In fact Oracle propagate it as well as a quick search with your favourite search engine will show. In my example I came across a system that used different listeners per database, which is very common and prevents users from “accidentally” connecting to the wrong system. If you are using such a setup please read on. If you are not using Oracle Restart/Clusterware/RAC then this is not immediately relevant to your Oracle estate.

fritshoogland's picture

Oracle IO on linux: database writer IO and wait events

This post is about database writer (dbwr, mostly seen as dbw0 nowadays) IO.
The testenvironment in which I made the measurements in this post: Linux X64 OL6u3, Oracle 11.2.0.3 (no BP), Clusterware 11.2.0.3, ASM, all database files in ASM. The test environment is a (VMWare Fusion) VM, with 2 CPU’s.

It might be a good idea to read my previous blog about logwriter IO.

The number of database writers is depended on the number of CPU’s visible to the instance (when not explicitly set with the DB_WRITER_PROCESSES parameter), and seems mostly to be CEIL(CPU_COUNT/8). There might be other things which could influence the number (NUMA comes to mind). In my case, I’ve got 2 CPU’s visible, which means I got one database writer (dbw0).

martin.bach's picture

RAC in KVM is possible without iSCSI

(This post is for Jerry. He will know when he reads it)

I have been a great supporter of many flavours of virtualisation and my earliest experience with Xen goes back to Oracle VM 2 which was based on RHEL 4 and an early version of Xen. Why am I saying this? Because Xen is (was?) simple and elegant. Especially for building RAC systems: paravirtualised Linux was all you needed, and a dual-core machine: Xen is very lightweight even though recent achievements in processor architecture (nested page tables, single root IO virtualisation, others) make it more desirable to use hardware virtualisation with paravirtualised drivers. This is what this post is about!

Shared storage in Xen

As you know you need shared block devices for RAC for voting disks, OCR, data files, redo logs, the lot. In Xen that’s as straight forward as it gets:

fritshoogland's picture

Oracle IO on linux: log writer IO and wait events

This post is about log writer (lgwr) IO.
It’s good to point out the environment on which I do my testing:
Linux X64 OL6u3, Oracle 11.2.0.3 (no BP), Clusterware 11.2.0.3, ASM, all database files in ASM.

In order to look at what the logwriter is doing, a 10046 trace of the lgwr at level 8 gives an overview.
A way of doing so is using oradebug. Be very careful about using oradebug on production environments, it can/may cause the instance to crash.

This is how I did it:

SYS@v11203 AS SYSDBA> oradebug setospid 2491
Oracle pid: 11, Unix process pid: 2491, image: oracle@ol63-oracle.local (LGWR)
SYS@v11203 AS SYSDBA> oradebug unlimit
Statement processed.
SYS@v11203 AS SYSDBA> oradebug event 10046 trace name context forever, level 8
Statement processed.

Of course 2491 is the Linux process id of the log writer, as is visible with “image”.

martin.bach's picture

Support for Pluggable Databases in Enterprise Manager

Currently there is an interesting thread on the oracle-l mailing list about OEM 12c support for database 12c Release. Unlike previous OEM generations this time OEM was not lagging behind. I am using OEM 12.1.0.2.0 with the database plugin 12.1.0.3.0 and yes, I can see PDBs!

pdbs-001

The above snapshot is from the database targets overview page. As you can see there is a Container Database (CDB1) and it has exactly 1 PDB. When you click on the CDB you get to the main page:

martin.bach's picture

DBMS_FILE_TRANSFER potentially cool but then it is not

This post is interesting for all those of you who plan to transfer data files between database instance. Why would you consider this? Here’s an excerpt from the official 12.1 package documentation:

The DBMS_FILE_TRANSFER package provides procedures to copy a binary file within a database or to transfer a binary file between databases.

But it gets better:

The destination database converts each block when it receives a file from a platform with different endianness. Datafiles can be imported after they are moved to the destination database as part of a transportable operation without RMAN conversion.

So that’s a way not only to copy data files from one database to another but it also allows me to get a file from SPARC and make it available on Linux!

martin.bach's picture

Creating a 12c Container Database from scripts

If you are curious how to create a CDB without the help of dbca then the “generate scripts” option is exactly the right approach! I am a great fan of creating databases with the required options only-the default template (General Purpose) is dangerous as it creates a database with options you may not be licensed for and additionally opens security risk.

The best^H^H^Heasiest way to understand how a Container Database (CDB from now on) is created is to let dbca create the scripts. The process is the same as with an interactive installation except that at the very end you do NOT create the database but tick the box to generate the scripts.

The resulting scripts will be created in $ORACLE_BASE/admin/${ORACLE_SID}/scripts. Change directory to this location and you will be surprised about the sheer number of files ending in *.sql

martin.bach's picture

Adding a node to a 12c RAC cluster

This post is not in chronological order, I probably should have written something about installing RAC 12c first. I didn’t want to write the tenth installation guide for Clusterware so I’m focusing on extending my two node cluster to three nodes to test the new Flex ASM feature. If you care about installing RAC 12c head over to RAC Attack for instructions, or Tim Hall’s site. The RAC Attack instructions are currently being worked at for a 12c upgrade, you can follow/participate the work on this free mailing list.

The cluster I installed is based on KVM on my lab server. I have used Oracle Linux 6.4 with UEK2 for the host OS. It is a standard, i.e. not a Flex Cluster but with Flex ASM configured. My network configuration is as shown:

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