Oracle 11g automated Healthchecks service

Oracle 11g Tips by Burleson Consulting
October 27, 2007

Oracle health checks are an integral task for the Oracle DBA and Oracle 11g has introduced a new service and software to assist in performing health checks.

As of 11g, Oracle Corporation has two new health check offerings:

A premium healthchecks service
A free health monitor using dbms_hm

For a moment, let's suspend Oracle Technical Support horrible reputation for technical incompetence, and see if these health checks have any merit.

WARNING: There have been warnings from the Oracle community that running the healthcheck service might expose privacy and licensing issues, prompting Oracle Corporation to conduct a license audit. For example, one foreign remote DBA provider says that full-disclosure with Oracle support might be embarrassing for companies that are running illegitimate copies of Oracle:

"I can understand how a person could comfortably conceal the fact that their test environment runs a binary compatible clone of a supported operating system, rather than the (much more expensive) commercial release.

In situations like that, Oracle Support could (okay, maybe legitimately) deny that person service"

Let's take a quick look at these 11g automated health check features and wee how they compete with a Oracle health check by a human Oracle expert.

At fist glance, neither of these "health check" tools and services match the comprehensive checks performed by Oracle monitoring experts, but it's a start, not a replacement for a human expert, but a step towards automation of health monitoring.

The heathcheck invokes resource intensive daemon process called nmccollector.exe

Oracle Healthchecks premium service

The Oracle Healthchecks service uses Oracle Configuration Manager and is part of a MOSC Premium service.

Source: Oracle Blogs

Also, the term "Healthchecks" refers only a check of a small sub-set of potential health issues and focuses solely on a limited number of configuration issues.

The premium Oracle service says that it checks little more than basic configuration issues:

"checking top database configuration issues; checking database host and highlighting incorrect parameter usage; and recommending improvements in table and index layout, storage management, table space allocation, and performance."

"HealthChecks are built from knowledge gained through resolving customers? most pressing support problems and from Oracle Support best practices, providing you with automated recommendations on your configurations.

These checks identify potential issues that may affect the overall stability, performance, and scalability of your Oracle environment and inform you of the risks associated with these issues."

Also note some privacy concerns with using Oracle Configuration Manager. These relate to the automatic collection and transmitting of data over a secured connection:

Source: Oracle Blogs

The 11g Health monitor

Oracle also has a free "health monitor" using the dbms_hm package:

Health monitor runs the following checks:

DB Structure Integrity Check?This check verifies the integrity of database files and reports failures if these files are inaccessible, corrupt or inconsistent. If the database is in mount or open mode, this check examines the log files and data files listed in the control file. If the database is in NOMOUNT mode, only the control file is checked.

Data Block Integrity Check?This check detects disk image block corruptions such as checksum failures, head/tail mismatch, and logical inconsistencies within the block. Most corruptions can be repaired using Block Media Recovery. Corrupted block information is also captured in the V$DATABASE_BLOCK_CORRUPTION view. This check does not detect inter-block or inter-segment corruption.

Redo Integrity Check?This check scans the contents of the redo log for accessibility and corruption, as well as the archive logs, if available. The Redo Integrity Check reports failures such as archive log or redo corruption.

Undo Segment Integrity Check?This check finds logical undo corruptions. After locating an undo corruption, this check uses PMON and SMON to try to recover the corrupted transaction. If this recovery fails, then Health Monitor stores information about the corruption in V$CORRUPT_XID_LIST. Most undo corruptions can be resolved by forcing a commit.

Transaction Integrity Check?This check is identical to the Undo Segment Integrity Check except that it checks only one specific transaction.

Dictionary Integrity Check?This check examines the integrity of core dictionary objects, such as tab$ and col$. It performs the following operations:

Verifies the contents of dictionary entries for each dictionary object.

Performs a cross-row level check, which verifies that logical constraints on rows in the dictionary are enforced.

Performs an object relationship check, which verifies that parent-child relationships between dictionary objects are enforced.

Also, see my notes on 11g health monitoring:

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