Databases at CERN blog

XFS on RHEL6 for Oracle - solving issue with direct I/O

Recently we were refreshing our recovery system infrastructure, by moving automatic recoveries to new servers, with big bunch of disks directly connected to each of them. Everything went fine until we started to run recoveries - they were much slower than before, even though they were running on more powerful hardware. We started investigation and found some misconfigurations, but after correcting them, performance gain was still too small.

How to create your own Oracle database merge patch

A little bit scary title, isn't it? Please keep in mind that definitely it is neither supported nor advised method to solve your problems and you should be really careful while doing it - hopefully not on production environment. But it may sometimes happen that you end up with the situation where creating your own merge patch for Oracle database could not be as crazy idea as it sounds :).

CHEP 2015 papers on replication and scale-out databases

CHEP 2015, the 21st international conference on computing in high energy physics, has taken place in April 2015 in Okinawa, Japan. Here below you can find the links to the pdf of the talks, posters and related preprints of two of the contributions by members the CERN database group. These are on the topics of our tests with scale-out databases (in particular on the Hadoop platform) and on the evolution of the replication technologies used for our Oracle databases (our use of Streams, GoldenGate and Active Data Guard):

Nuances of Oracle Managed Files (OMF) and RMAN

Oracle Managed Files (OMF) have many advantages, but the fact that such files could coexist in the same database with manually added (and named) ones, could sometimes lead to confusion. Situation is made worse by the fact, that there is no straightforward way (at least of which I'm aware of...or rather was - please check the comment of Mikhail Velikikh) to say if the file is Oracle managed or not. Oracle documentation seems to confirm this:


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