Ontrack Recovers Data from 1.6 Terabyte Oracle Database

Written By: Ontrack

Date Published: Sep 19, 2011 12:00:00 AM

Ontrack Recovers Data from 1.6 Terabyte Oracle Database

A major property surveyor operating in Spain lost access to a 1.6 terabyte Oracle 10 database following a power failure and contacted Kroll Ontrack data recovery specialists through his authorized partner. Kroll Ontrack experts immediately engaged to consult with the customer and investigate the potential recovery options.

The client was running Oracle 10 on SuSe Linux, with the databases stored in an ASM volume on an HP EVA SAN system with 20 drives. However, when attempting to power up the system after the electrical failure, it would not mount. The client consulted with its hardware supplier and ascertained that two drives in the HP EVA SAN had failed. The critical file on the system – a database with years’ worth of data related to property valuations required by clients and tax purposes – had not been backed up.


The client contacted Kroll Ontrack through an authorized partner and requested a proposal for recovery of the database. Given the potential complexity of the recovery, Kroll Ontrack requested access to perform preliminary testing on the hardware and determined:

  • The two failed drives needed physical repair and data recovery in a clean room environment.
  • There was a high level of probability that the research and development team would need to be engaged to produce new repair tools for the HP EVA or ASM configurations.

As a result, the client was presented with a proposal comprised of multiple service delivery options to match their budget and time constraints.


The client decided to engage Kroll Ontrack data recovery specialists to perform the following services:

  • Clean room engineers used proprietary techniques to recover all data structures from the two failed drives.
  • Structural engineers could not interpret the data structures of the specific HP EVA version. However, using reverse engineering techniques on a production EVA environment of similar specification, Kroll Ontrack research and development engineers discovered the data mapping used by the system. As a result, an existing toolset was updated to allow assembly of the LUNs on the clients’ system.
  • Proprietary ASM recovery tools were used to extract the Oracle database structures from the LUNs.
  • Proprietary Oracle recovery tools were used to recover tables into SQL Loader import files and provided them to the client.  This required adding support for the “Bigfile” tablespace to the existing recovery tools. Of the 650 tables and over 82 million rows of Oracle data found, recovered and provided to the client in working format, only 1.515 rows of non-essential data were not fully recovered. The client successfully imported all data into their system.


Database Recovery


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