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October 08, 2012



Interesting preview of database approaches in the pipeline.

From personal experience, we saw a slow movement of our clients from managing physical server boxes to vmWare virtualization, and I'd say about 50% of our client-base is still on physical boxes.

I think you hit the nail on the head when talking about DBA proficiency. You'd be dumbfounded by the general skill-level of DBA's NOT in high tech verticals or Silicon Valley. I've worked with government agencies, counties, healthcare providers, etc, and simplicity is a requirement if you want to get anything done.

While pluggable databases might be attractive from a Database developer's perspective, the licensors of these technologies are typically CTOs and CIOs. These are people that stake their reputation on new IT initiative working quickly and smoothly. I don't see a big shift to a new database architecture just as virtualization is taking root in general industry. My two cents though....

--David Waugh--

Chuck Hollis


Good points and observations, thanks for sharing!

-- Chuck

Alex Fatkulin

Memory efficiency still remains a difference. When each database needs it's own private memory which it doesn't share with anybody else you need a lot of memory to run a lot of separate databases on the same machine. With Pluggable databases the memory is shared because it's a single Oracle instance running it all. Thus I don't see Pluggable databases as much a competitor for virtualization but as complementary feature mainly targeted at reducing resource (mainly memory) footprint.


You can run a DBMS on a virtual machine, you can support multi-tenancy inside the DBMS, or you can support a fully virtualized database, where you abstract between compute and storage (like Serengeti does for Hadoop and ScaleDB does for MySQL). Here is a write-up of the challenges, solutions and benefits of true database virtualization: http://www.scaledb.com/database-virtualization.php

Kyle Hailey

To see a comparison of database virtualization technologies check out


Putting a database in a virtual machine is still just virtualizing the compute tier i.e. the operating system. Database virtualization, as opposed to operating system virtualization, is sharing a read only copy of a source database between clone databases. The clone databases are called virtual databases (also called thin provision clones as distinct from full physical copy clones). Virtual databases are much more than simple read only databases. The virtual databases can also write to the data files. How can the virtual databases write to the data file when the data files are read only? Writing to the data files is accomplished either through one of two basic mechanisms. Those mechanisms are pointer based copy on write file systems or journal file systems. When a virtual database writes to the data files the changes are not written to the data file but are kept in a private area only visible to that virtual database. Each virtualized database sees what appears to be a private read/write copy of the database. Database changes made by a virtual database are only seen by that virtual database as if the virtual database had its own full private copy of the source database.

Database Virtualization gives:

1. Enormous storage savings.
2.Instant provisioning of virtual databases.

A virtual database can be made in seconds and takes up almost no space. The datafiles are full shared initially so initially take up almost no space.

Now combining compute virtual machines, pluggable databases and virtual databases will provide enormous hardware savings and more importantly unprecedented agility.

- Kyle Hailey

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Chuck Hollis

  • Chuck Hollis
    SVP, Oracle Converged Infrastructure Systems

    Chuck now works for Oracle, and is now deeply embroiled in IT infrastructure.

    Previously, he was with VMware for 2 years, and EMC for 18 years before that, most of them great.

    He enjoys speaking to customer and industry audiences about a variety of technology topics, and -- of course -- enjoys blogging.

    Chuck lives in Vero Beach, FL with his wife and four dogs when he's not traveling. In his spare time, Chuck is working on his second career as an aging rock musician.

    Warning: do not ever buy him a drink when there is a piano nearby.

    Note: these are my personal views, and aren't reviewed or approved by my employer.
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