Wednesday, December 4, 2013

Querying an Oracle VM Server Xenstore from a Linux Guest

Accessing the Oracle VM Xenstore from a Linux Guest is the most efficient and sometimes most reliable way to collect data about your Oracle virtualized environment. Among the various things you can get from Xen internal database are (1) the DomU name, (2) the Dom0 VNC access point or (3) the mapping between the VM disk devices and the underlying storage.

For instance, if you want to trigger a storage snapshot from your guest, you can directly and automatically discover the LUN serial number with the xenstore-ls command and request a snapshot without connecting to the Oracle VM Manager.

This article explains how to install and use the various xenstore tools/utilities to get those values.

Tuesday, December 3, 2013

Custom DTrace Probes for Perl on Oracle Linux 6

Chris Andrews (@chrisandrews) has developed the libusdt library a few years back so that dynamic language developers can publish custom DTrace providers easily. He has also developed the associated modules for Ruby, Perl and Node.js... If you are dealing with one of these languages, publishing a DTrace provider usually takes no more than 5 lines.

Last September, Chris has adapted his library so that it works with Oracle Linux 6 DTrace and the Unbreakable Enterprise Kernel 3. This post explains how to use Perl Devel::DTrace::Provider module in this context.