Sharing GoldenGate directories in RAC environments

Posted in: Technical Track

GoldenGate operates in an active/passive capacity for RAC databases. When installing GoldenGate on a local host, certain directories are required to be on shared storage.

I will share my opinions for which directories should be placed on shared storage.

Determine GoldenGate versions and directories created from ggsci:

GGSCI 8> versions

Operating System:
Linux
Version #2 SMP Wed Apr 25 19:57:32 PDT 2018, Release 4.1.12-94.8.3.el7uek.x86_64
Node: ihotloral01.ilcb.tcprod.local
Machine: x86_64

Database:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
PL/SQL Release 12.1.0.2.0 - Production
CORE	12.1.0.2.0	Production
TNS for Linux: Version 12.1.0.2.0 - Production
NLSRTL Version 12.1.0.2.0 - Production

GGSCI 9> show


Parameter settings:

SET SUBDIRS    ON
SET DEBUG      OFF

Current directory: /u03/app/gg/12.2.0

Using subdirectories for all process files

Editor:  vi

Reports (.rpt)                 /u03/app/gg/12.2.0/dirrpt
Parameters (.prm)              /u03/app/gg/12.2.0/dirprm
Replicat Checkpoints (.cpr)    /u03/app/gg/12.2.0/dirchk
Extract Checkpoints (.cpe)     /u03/app/gg/12.2.0/dirchk
Process Status (.pcs)          /u03/app/gg/12.2.0/dirpcs
SQL Scripts (.sql)             /u03/app/gg/12.2.0/dirsql
Database Definitions (.def)    /u03/app/gg/12.2.0/dirdef
Dump files (.dmp)              /u03/app/gg/12.2.0/dirdmp
Masterkey wallet files (.wlt)  /u03/app/gg/12.2.0/dirwlt
Credential store files (.crd)  /u03/app/gg/12.2.0/dircrd


GGSCI 10>

The following directories must be on local host:

dirpcs
dirdb

“Do not place the dirpcs directory on the shared file system. Problems can occur when the process information contained in the process files do not match the host where the process is currently being startedafter a RAC node failure.

If creating a datastore for use by JAgent on the Oracle GoldenGate Performance Metric Server, the dirbdb directory should also be created on local storage.”  Reference: Oracle GoldenGate with Oracle Real Application Clusters Configuration Best Practices

Following Oracle RAC database implementations, the following directories are preferred to be on the local host:

dirtmp
dirrpt
dirdmp

The following directories should be on shared storage:

dirprm
dirchk
dirdef
dirwlt
dircrd

Create symbolic links from local host to shared storage. The following directory should be created directly on share storage:

BR (Bounded Recovery)

Based on the above implementation, minimum directories are on shared storage using symbolic links.

Why is this important? BUGS!

Opatch Failed To Install Patch 18507404 with NO Such Device (Doc ID 2072943.1)

CAUSE
Symbolic links causing the issue.
Traversing via soft link.

SOLUTION
It appears to be an issue while traversing via soft link or a probable performance issue as it is unable to identify the device (in your case DBFS) where the Soft link has been created to and no root cause has been identified as such.

From the GoldenGate prespective, Please drop the soft link for the patching to succeed and once done re-create the soft link.

Even though the note is specific for Patch 18507404, the solution was also applicable for Patch 26849949.

In conclusion, while it may be tempting to put all directories on a shared storage, placing only the required directories on shared storage may help to avoid bugs and simplify troubleshooting from having to review fewer files and only pertinent files, to name a few.

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