Why does the size of my ORACLE_HOME increase?

Recently I discovered that the size of an ORACLE_HOME for a given release varies from machine to machine although the machines are of the same architecture and run the same operating system. A small difference in size can be explained by the fact that one ORACLE_HOME was re-linked in the past while the other wasn’t, but this time the difference was more than 1 GByte. Digging a bit further revealed a sub-directory called .patch_storage which, as the name implies, is used to store patch related data.

I found NOTE:550522.1 on MyOracleSupport which describes what this directory is used for and why it suddenly so big. It turns out that recent versions of OPatch, installed by installing patch 6880880, not only store object files (several kilo byes in size) that are patched in $ORACLE_HOME/.patch_storage but also the library (several tens of mega bytes in size) in which the affected object file belongs. This is to make rolling back installed patches as quick as possible. Thus in effect this is a space-for-time issue. Because OPatch doesn’t clean the .patch_storage directory up whenever files are no longer needed because a more recent patch gets installed the size of an ORACLE_HOME increases without notice.

The good news is that recent versions of OPatch have an option to clean up the .patch_storage directory manually if one doesn’t like this space-for-time optimization.

Let’s have a look at the current disk usage before cleaning up my .patch_storage directory.

$ cd $ORACLE_HOME
$ du -hs .patch_storage
1.2G    .patch_storage

The above shows that I currently have 1.2 GByte in the .patch_storage directory. This is an Oracle 11g Release 1 (11.1.0.7.0) ORACLE_HOME with the latest PSU and a few interim patches applied.

The opatch util cleanup command is used to clean up the .patch_storage but before doing so let’s have a look at the OPatch help output for this command.

$ opatch util cleanup -help
Invoking OPatch 11.2.0.1.1

Oracle Interim Patch Installer version 11.2.0.1.1
Copyright (c) 2009, Oracle Corporation.  All rights reserved.

UTIL session

DESCRIPTION
     This utility cleans up 'restore.sh,make.txt' files and 'rac,scratch,backup' 
     directories of the.patch_storage directory of Oracle Home.If -ps option is used, 
     then, it cleans the above specified areas only for that patch, else for all 
     patches under ORACLE_HOME/.patch_storage. You will be still able to
     rollback patches after this cleanup.

SYNTAX
opatch util cleanup  [-invPtrLoc <Path to oraInst.loc> ]
                     [-jre <LOC> ] [-oh <ORACLE_HOME> ]
                     [-silent] [-report]
                     [-ps <patch ID with time stamp>, this will
                       be located under ORACLE_HOME/.patch_storage/]

OPTIONS   
       -invPtrLoc
              Used to locate the oraInst.loc file. Needed when the
              installation used the -invPtrLoc flag. This should be
              the path to the oraInst.loc file.

       -jre
              This option tells OPatch to use JRE (java) from the
              specified location instead of the default location
              under Oracle Home. Both -jdk and -jre options cannot
              be specified together. OPatch will display error in
              that case.
            
       -oh
              The oracle home to work on. This takes precedence over
              the environment variable ORACLE_HOME.
         
       -ps
              This option is used to specify the Patch ID with timestamp.
              This Patch ID with timestamp should be the same as in
              .patch_storage directory.

              A directory by this name will be present under
              ORACLE_HOME/.patch_storage. If this directory is specified
              and is valid, then the contents specified in the description
              will be cleaned up only for this patch. Otherwise, all patch
              related directories will be acted upon by this utility.

      -silent 
              In silent mode, the cleanup always takes place.

      -report 
              Prints the operations without actually executing them.


OPatch succeeded.

With this knowledge we can proceed with the actual clean up as shown below:

$ opatch util cleanup
Invoking OPatch 11.2.0.1.1

Oracle Interim Patch Installer version 11.2.0.1.1
Copyright (c) 2009, Oracle Corporation.  All rights reserved.

UTIL session

Oracle Home       : /u01/app/oracle/product/11.1.0
Central Inventory : /u01/app/oraInventory
   from           : /etc/oraInst.loc
OPatch version    : 11.2.0.1.1
OUI version       : 11.1.0.7.0
OUI location      : /u01/app/oracle/product/11.1.0/oui
Log file location : /u01/app/oracle/product/11.1.0/cfgtoollogs/opatch/opatch2010-02-20_15-27-15PM.log

Patch history file: /u01/app/oracle/product/11.1.0/cfgtoollogs/opatch/opatch_history.txt

Invoking utility "cleanup"
OPatch will clean up 'restore.sh,make.txt' files and 'rac,scratch,backup' directories.
You will be still able to rollback patches after this cleanup.
Do you want to proceed? [y|n]
y
User Responded with: Y
Size of directory "/u01/app/oracle/product/11.1.0/.patch_storage" before cleanup is 1256452888 bytes.
Size of directory "/u01/app/oracle/product/11.1.0/.patch_storage" after cleanup is 142265128 bytes.

UtilSession: Backup area for restore has been cleaned up. For a complete list of files/directories
deleted, Please refer log file.

OPatch succeeded.

OPatch started by displaying the amount of disk usage in the .patch_storage directory before asking for permission to perform the actual clean up. Once the clean up is finished OPatch reports the new amount of disk usage. We can easily verify that OPatch indeed freed up a fair amount of disk space by running the du –hs command.

$ du -hs .patch_storage
144M    .patch_storage
 

In short: Running opatch util cleanup after installing patches prevents your ORACLE_HOME from eating up too much disk space without losing the ability from rolling back those patches.
-Harald