Topic: this post is about some simple tools and techniques that can be used to drill down high-latency I/O events using SystemTap probes.
Databases at CERN blog
Topic: This post is about collecting and visualizing I/O latency histograms for NetApp filers in C-mode.
Regular readers of our blog probably already know that for most of our databases we're using two storage layers to keep our backups - NAS volumes as a primary layer and tapes as secondary one - please check "Datafile without backups - how to restore?" for more details. If you read another post "Importance of testing yours ba
Topic: event histogram metric, a script and some related discussions on collecting and displaying wait event latency histograms for Oracle performance troubleshooting.
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):
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:
Real-life scenario describing troubleshooting of instance startup problems and actions needed to solve them.
Since version 11.1 of Oracle database, there is very useful command available, allowing DBAs to easily move RMAN recovery catalog schemas between databases. Its functionality is even broader, as it also allows one catalog schema to be merged into another - either the whole schema or just the metadata of chosen databases. Command I'm writing about is of course import catalog, which I had a chance to use recently, to move our recovery catalog to the new database.