11g Change: Alert log is missing in $OH/admin/SID/bdump

Hello Everyone!!

Today I thought to write new changes happened in 11g DB with respect to alert log location.
As a DBA we tend monitor alert log for any DB related errors, messages, warnings.

In 11i Ebiz suite with 10g DB, By default, alert log is placed in $ORACLE_HOME/admin/$CONTEXT_NAME/bdump directory with the name alert_sid.log

you can get the bdump location from init.ora. in this example my environment name is r12test

-bash-2.05b$ grep dump initr12test.ora
user_dump_dest = /slot01/appmgr/R12/db/tech_st/10.2.0/admin/r12test_ap6155rt/udump
background_dump_dest = /slot01/appmgr/R12/db/tech_st/10.2.0/admin/r12test_ap6155rt/bdump
core_dump_dest = /slot01/appmgr/R12/db/tech_st/10.2.0/admin/r12test_ap6155rt/cdump

in 11g DB, alert log location, trace files are getting generated in new format in new locations.
This is part of diagnosability enhancement in oracle 11g.

user_dump_dest,background_dump_dest,core_dump_dest init.ora parameters are repaced by parameter diagnostic_dest

New Location is

$ORACLE_HOME/admin/$CONTEXT_NAME/diag/rdbms/DBNAME/INSTANCENAME/trace

With Release 11g, Oracle Database includes an advanced fault diagnosability infrastructure for collecting and managing diagnostic data. Diagnostic data includes the trace files, dumps, and core files that are also present in previous releases, plus new types of diagnostic data that enable customers and Oracle Support to identify, investigate, track, and resolve problems quickly and effectively.

What is ADR?

The Automatic Diagnostic Repository (ADR) is a file-based repository for storing diagnostic data. Because this repository is stored outside the database, the diagnostic data is available even when the database is down. As of Release 11g, the alert log, all trace and dump files, and other diagnostic data are also stored in the ADR.

What is an ADR HOME?

An ADR HOME is the root directory for all diagnostic data—traces, dumps, the alert log, and so on. The location of an ADR home is given by the following path

*diagnostic_dest*/diag/product_type/product_id/instance_id

e.g
alert log location is
/slot01/tkr12r3m/db/admin/tkr12r3m2_rws60002tch/diag/rdbms/tkr12r3m/tkr12r3m2/trace

where tkr12r3m2 is instance id, tkr12r3m is database name
Database Alert log is given as xml file as well as plain text file.

10g Vs 11g

Diagnostic Data	Previous Location 10g R2	ADR Location
Database Alert log File	BACKGROUND_DUMP_DEST	ADR HOME/alert /log.xml ADR HOME/trace/alert_.log
Background Process Trace Files	USER_DUMP_DEST	ADR HOME/trace
Foreground Process Trace Files	BACKGROUND_DUMP_DEST	ADR HOME/trace

Hope this helps when you start working in 11g.