Using Linux /proc To Identify ORACLE_HOME and Instance Trace Directories.

I recently had a co-worker access one of my systems running Oracle Database 11g. He needed to poke around with focus on an area that he specialized in. After getting him access to the server I got an email from him asking where the trace files are for the instance he was investigating.

This is one of those Carry On Wayward Googler™  sort of posts. Most of you will know this, but it may help someone someday. It did help my co-worker as this was the way I answered his question.

You can find out a lot about an instance without even knowing which ORACLE_HOME it is executing out of by spelunking about in /proc. In the following text box you’ll see how to find the ORACLE_HOME and trace directories for an instance by looking at /proc/<PID>/fd and /proc/<PID>/exe of the LGWR process. This box had an instance called test and an ASM instance. So in this case the ORACLE_HOME values were /u01/app/oracle/product/11.2.0/dbhome_1 and /u01/app/11.2.0/grid.

$ ps -ef | grep lgwr | grep -v grep
oracle    3548     1  0 Sep02 ?        00:00:27 ora_lgwr_test3
oracle    8734     1  0 Sep02 ?        00:00:00 asm_lgwr_+ASM3
$ ls -l /proc/8734/exe /proc/3548/exe
lrwxrwxrwx 1 oracle oinstall 0 Sep  2 21:09 /proc/3548/exe -> /u01/app/oracle/product/11.2.0/dbhome_1/bin/oracle
lrwxrwxrwx 1 oracle oinstall 0 Sep  2 11:09 /proc/8734/exe -> /u01/app/11.2.0/grid/bin/oracle
$ ls -l /proc/8734/fd  /proc/3548/fd | grep trace | grep -v grep
l-wx------ 1 oracle oinstall 64 Sep  2 21:09 11 -> /u01/app/oracle/diag/rdbms/test/test3/trace/test3_ora_3501.trc
l-wx------ 1 oracle oinstall 64 Sep  2 21:09 12 -> /u01/app/oracle/diag/rdbms/test/test3/trace/test3_ora_3501.trm
l-wx------ 1 oracle oinstall 64 Sep  2 11:09 16 -> /u01/app/oracle/diag/asm/+asm/+ASM3/trace/+ASM3_ora_8636.trc
l-wx------ 1 oracle oinstall 64 Sep  2 11:09 17 -> /u01/app/oracle/diag/asm/+asm/+ASM3/trace/+ASM3_ora_8636.trm

4 Responses to “Using Linux /proc To Identify ORACLE_HOME and Instance Trace Directories.”

  1. 1 Tanel Poder September 3, 2009 at 7:09 pm

    Yeah, linux proc filesystem is especially nice as lots of files there are readable and dont need special programs for parsing their binary contents (as opposed to solaris /proc for example)

    I’ve used pmap on linux and other Unixes for same purposes, such identifying which processes use which oracle homes etc.

  2. 2 Amit September 4, 2009 at 5:14 am

    Thanks Kevin.. I was looking for this since long time :)) pmap option from Tanel also looks interesting approach for other flavors of Unix ..


  3. 3 Bernd September 6, 2009 at 2:32 am

    dont forget about lsof, as well.

  1. 1 Log Buffer #160: a Carnival of the Vanities for DBAs | Pythian Group Blog Trackback on September 4, 2009 at 5:08 pm

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