Read Oracle Linux 7 Beta 1

It might be too late posting about Oracle Linux 7 (Beta 1). Just came back from long holidays in Thailand. I think it's very interesting to learn something new in OL7. Users can download it by using OTN account.
Download.
Release Note.

After installed it, I tested some a little bit.
[root@ol7beta ~]# cat /etc/oracle-release
Oracle Linux Everything release 7.0 Beta
[root@ol7beta ~]# uname -r
3.8.13-31.el7uek.x86_64
Users can choose to (more...)

The Ultimate Guide To Oracle with Advanced Format 4k

fud

It’s a brave thing, calling something the “Ultimate Guide To …” as it can leave you open to criticism that it’s anything but. However, this topic – of how Oracle runs on Advanced Format storage systems and which choices have which consequences – is one I’ve been learning for two years now, so this really is everything I know. And from my desperate searching of the internet, plus discussions with people who are usually much knowledgeable than (more...)

Duplicate from the standby instead from the primary in 12c

This post is related to 12c and an active database duplication for a standby I did in my lab environment. I’d say although I first encountered it on 12c there is a chance you run into a similar situation with earlier releases too.

I would normally use ASM for all my databases to make my life easier but this time I had to be mindful of the available memory on the laptop-which at 8 GB-is (more...)

Ubuntu upgrade to 12.04: grub timeout does not work anymore

After doing the upgrade and solving some issues with my screen-resolution, another grub problem hit me:
The timeout for booting the standard kernel did not work anymore.
Inside /etc/default/grub
GRUB_TIMEOUT=10
and update-grub, grub worked like
 GRUB_TIMEOUT=-1
If you need a  good manual  just look here, but this does not help me, too.

After some tries, i did the following:

In /boot/grub/grub.cfg i changed from
terminal_output gfxterm
if [ "${recordfail}" = 1 ] (more...)

Ubuntu upgrade to 12.04: screen only works with 1024×768

After upgrading a laptop-system to 12.04 (precise pangolin) X only starts with a resolution of 1024x768 and not with 1366x768.
I followed many postings and tried many things:
  • add new resolution with xrandr (here)
  • create a xorg.conf file (here)
  • add new drivers (here)
  • ...
But there was only one thing wrong: /etc/default/grub

After changing the following line everything worked:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.modeset=0
to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
(i added (more...)

New installation cookbook for SUSE Linux Enterprise Server 11 SP3

Exactly what it says on the tin, I’ve added a new installation cookbook for SUSE 11 SP3 which creates Violin on a set of 4k devices.

I’ve started setting the add_random tunable of the noop I/O scheduler because it seems to give a boost in performance during benchmarking runs. If I can find the time, I will blog about this at some point…

For more details read this document from Red Hat.


Filed under: Blog, (more...)

Automated Linux VM build on ESX


How to automatically install RedHat like (Red Hat, Cent OS, Oracle Enterprise Linux) Linux system on ESX or VirtualBox servers ? There are at least two methods. I have seen VM cloning in lot of places using ESX (VSphere Center) or VirtualBox functionality. Cloning is fine but it required some intervention after clone will be finished (like host rename or IP address change). What if we want to install different releases of systems - well it (more...)

Recovering a standby over the network in 12c

Another one of the cool but underrated features in 12c is the possibility to recover a physical standby over the network with one line in RMAN.

Why do you need to perform this activity? Assume someone really clever created a segment “nologging” and the database was not in force logging mode. This operation cannot be replicated by redo apply on the standby, and you are bound to have a problem. Or, in my case, I (more...)

tweaking the entropy pool for a better SOA performance

At my current assignment, I’ve gone to great lengths to improve the Oracle SOA Enterprise Manager Console performance. One of the actions I took, was purging about 700 gigabytes of data from the dehydration store. Although that solved lots of other problems, the EM still wasn’t very responsive. Loading composite details could take op to 20 minutes, it they ever loaded at all. Apparently, the database was ok, because there was no load at all (more...)

Interesting GNS anomaly in 12.1.0.1.2 RAC

I was encountering an interesting anomaly with my 12.1.0.1.2 RAC cluster based on Grid Naming System. I have written about the setup here.

No need to get back to the post-instead let me give you some background if you are not familiar with the Grid Naming System in RAC. Most RAC installations use a Domain Name Server (DNS) to resolve names to IP addresses. In the case of GNS the name (more...)

Troubleshooting Oracle DBFS mount issues

On Exadata the local drives on the compute nodes are not big enough to allow larger exports and often dbfs is configured. In my case I had a 1.2 TB dbfs file system mounted under /dbfs_direct/.

While I was doing some exports yesterday I found that my dbfs wasn’t mounted, running quick crsctl command to bring it online failed:

[oracle@exadb01 ~]$ crsctl start resource dbfs_mount -n exadb01
 CRS-2672: Attempting to start 'dbfs_mount' on 'exadb01'
  (more...)

Linux strace doesn’t lie after all.

strace is a linux utility to profile system calls. Using strace you can see the system calls that a process executes, to investigate inner working or performance. In my presentation about multiblock reads I put the text ‘strace lies’. This is NOT correct. My current understanding is that strace does show every system call made by an executable. So…why did I make that statement? (editorial note: this article dives into the inner working of Linux (more...)

Installing PeopleTools Client on Ubuntu Linux Host

Ubuntu has been my choice of OS for some time now. It works great for the most part until I start trying to interact with the Microsoft-centric business world. App Designer is one of those pressure points. Normally, my clients give me a Windows-based remote desktop, but for playing around with things outside a client, I needed a way to run App Designer locally on my laptop.

I finally figured out how to install App (more...)

Investigating the wait interface via gdb.

For some time now, I am using gdb to trace the inner working of the Oracle database. The reason for using gdb instead of systemtap or Oracle’s dtrace (no link; doesn’t seem to have a homepage) is the lack of user-level tracing with Linux. I am using this on Linux because most of my work is happening on Linux.

In order to see the same information with gdb on the system calls of Oracle as (more...)

Oracle ASMLib: Physical and Logical Blocksize

This article is about the use of Advanced Format devices on Oracle’s ASMLib kernel library for Linux. For background, read this page on 4k sector sizes first, otherwise it might all sound like nonsense. Mind you, it mind sound like nonsense anyway, I can’t guarantee anything here. By the way, a big hello to my buddy Nate who asked for this information: you rock, dude.

In more recent versions of ASMLib, Oracle introduced a new (more...)

Finding And Deleting Old Files (on Unix and Windows)

I needed to write short scripts to delete old files on a Windows Server. It’s a very easy task on UNIX flavors but the limited capacity of Windows command line made me worried. You can use a simple “find” command to find old files on UNIX. For example, the following command will be enough to find and delete files older than 7 days:

find /folder/ -type f -mtime +7 -exec rm {} +

For the (more...)

OEM 12c installation fails if parallel_max_servers too high

Just a quick post regarding OEM 12c installation where recently I had to install OEM 12c and during the repository configuration step the installation fails with error:

ORA-12801: error signaled in parallel query server P151

This was caused by a known bug which requires decreasing the number of parallel queries of the repository databases and start over the installation. The database had cpu_count set to 64 and parallel_max_servers to 270. After setting the parallel_max_servers to (more...)

Runtime Load Balancing Advisory in RAC 12c-addendum

A reader asked an interesting question yesterday with regards to the previous post on the subject: where did you get your service metrics from when you queried v$servicemetric-PDB or CDB$ROOT?

I queried the PDB, but this morning repeated the test to make sure the results are consistent, and they are. This is definitely something you’d hope for: you should not have different results in the same v$-view depending on the container you execute your query (more...)

Runtime Load Balancing Advisory in RAC 12c

This is a follow-up on yesterday’s post about services in the new 12c database architecture. After having worked out everything I needed to know about TAF and RAC 12c in CDBs I wanted to check how FCF works with PDBs today. While investigating I found out that the Runtime Load Balancing Advisory does not seem to work as expected. To double-check, I ran the same test against a 12c non-CDB and noticed that the RTLB (more...)

ORA-13505

I tested this on an Oracle 10 database running on Linux. If you try to make the SYSAUX tablespace READ ONLY, you get an error. There is no way round this, you cannot do it: 

SQL> alter tablespace sysaux read only
  2  /
alter tablespace sysaux read only
*
ERROR at line 1:
ORA-13505: SYSAUX tablespace can not be made read only

SQL>