Exadata experience, what does that actually mean?
Posted by Martin Bach on April 5, 2012
As an active member of the Oracle user community I really enjoy talking to delegates at user conferences and user group meetings. As such I was very lucky having had the opportunity to attend two of them recently. I have written about the OUGN spring conference in the post before this, and I also enjoyed the AIM meeting earlier in March.
One of the subjects that always seems to come up is Exadata. Many, many DBAs want to have Exadata experience, and if only to tick a box. Now Exadata means a significant investment, in other words not every company on the planet will have one. On the other hand it’s reasonably complex to administer, therefore recruiters and other HR personal are very interested in DBAs with “Exadata experience”. Now, the reason of this blog post is an open question to the readers: what do you consider as Exadata experience?
Let me explain my reasoning. I have worked on a site with Exadata. I have logged in, I produced papers about the Smart Flash Cache, cell metric statistics, smart scans etc. Does that mean I have Exadata experience? Maybe yes. But then until recently I haven’t been involved in the One Command process. I worked my way through a huge PDF which asked all sorts of questions about the Exadata configuration. I have seen the resulting XLS file which is used to drive the configuration of the Exadata database machine. Unfortunately I didn’t have the opportunity to execute the OneCommand script myself-but I’ve seen the log files. Many Exadata DBAs haven’t seen this at all, because Oracle installed their Exadata system. Do they not have Exadata experience? Thought-provoking!
I also know a little bit about Real Application Clusters. I know about workload management and other features that aren’t widely used such as Universal Connection Pools, Fast Application Notification and the other related technologies. Does that mean I know everything there is to Exadata? Not at all-I know the concepts, and I know where to look for information. I would trust only very few people who claim they know everything about Exadata.
I think the bottom line is that there are very few people on the planet who really know enough. Most others will see a piece of the puzzle, which is not necessarily their fault but a procedural problem. In the days before 10.1 the world was simple: you had storage administrators, you had OS admins, and then database administrators. You would have used block-level SAN replication, Oracle 9i single instance and Forms and Reports 6i on Citrix Metaframe. Simple. Worked! If it got really fancy, you’d see a VCS or Power HA cold failover cluster (administered by the system admin).
Now we have Automatic Storage Management. The DBA intrudes into the world of the storage admin, and that is painful for both. We also have Oracle Clusterware: all over sudden we don’t need the system administrator to define Sun Cluster, HP ServiceGuard, SFRAC etc. So the DBA again intrudes into unknown terrain. There are many more examples, including dNFS, the Grid Naming System, Cluster Time Synchronisation, Fencing (remember IPMI?)
This change in point of view doesn’t work well with the old model which still is unchanged from the “old” days. And it gets worse when introducing Exadata. Who does what? Will the DBA administer the cells and the ASM disk groups-no way, that storage admin territory. But hey it also means the storage admin has to learn ASM…. What about patching the compute nodes-you are ideally logged in as root for opatch auto. But a DBA with root access!?!? Never. And so the DBA has to be content with what he has always done in 9i and not worry too much about the other components, which are nominally in the hands of the system and storage admin. Except when it breaks :)
So much for that, this is very much a European view, readers elsewhere may have different experience. Do YOU have Exadata experience?
This article has caused more interest than I assumed it would, so maybe a summary is in order
- Dear recruiter, when I’m stating I have Exadata experience, please don’t expect me to be able to answer each and every answer. Depending on what I did I simply didn’t have exposure to xyz.
- Companies implementing Exadata should try to embrace the change.
I’m in no way critical of Exadata, in fact I really enjoy it! Infiniband, fast processors, Real Application Cluster, Data Guard… all the right ingredients to keep me happy.