Soft link for Oracle or Oracle client install on hpux

[Shivkumar]

Hi,

We installed oracle 9.2.x client in non-default directory ( say /opt/rose/bigguy/oracle) but had to create a soft link as "/opt/oracle" later to function it properly.

My question is why do we need to create soft link when all the binaries and software components resides at /opt/rose/bigguy/oracle ?

Why the softwares are coded to look for certain directory always ?

Thanks,
Shiv

[Pete Randall · Accepted solution]

Shiv,

I'm afraid you would have to ask Oracle that question. They certainly don't have to do it that way but for some reason, they did.


Pete

[James R. Ferguson]

Hi Shiv:

When writing software, one has to specify *some* path to components. If the only specification is a relative path, then all of the software components would have to reside in the same working directory.

That doesn't provide great or easy flexability.

In the case you describe, consider what happens if *after* installation you want to move your installed software to another location. Its now easy. Create a symbolic link that points '/opt/oracle' to somewhere else.

Does this clarify the rationale?

Regards!

...JRF...

[A. Clay Stephenson]

Well written software packages will generally make some default assumptions just in case you are too lazy to properly setup the environemnt. In almost all cases, one is allowed to override these defaults using environment variables. In the case of Oracle, the environment variable ORACLE_HOME which might be derived from ORACLE_BASE generally takes care of this. In fact, it's possible to have Oracle8, 9, & 10 running on the same server, multiple instances of each, and none installed in /opt/oracle.

[Yogeeraj_1]

hi shiv,

to add to above replies.

With Oracle you should adopt the ORACLE FLEXIBLE ARCHITECTURE (OFA) for directories.

See note 1006754.6 on metalink.

For example, the control files for a database in the OFA directory structure looks as follows:

$ORACLE_BASE/data//control01.ctl
$ORACLE_BASE/data//control02.ctl
$ORACLE_BASE/data//control03.ctl

(see metalink note 1006756.6)

I also believe that since there are multiple flavours of Unix, they tend to keep things "standard"...

hope this helps too!

kind regards
yogeeraj

[Volker Borowski]

Hi Shiv,

well there are two options for Software, which is using dynamic libraries.

1) Be flexible and use Environment to configure it -> i.E. let LD_LIBRARY_PATH or in case of HP-UX SHLIBPATH point to the directory where the libs are.
-> Pro: flexible
-> Con: Libs can be spoofed, by fooling Environment

2) Hardcode the location
-> Con: less flexible
-> Pro: Need access to original location to spoof the libs (more difficult).

It depends, on how your application has been compiled when the oracle-client libs have been specified. You CAN build the SW with options to allow the SW to find the libs using SHLIBPATH environment.

A native oracle-client can be locatd elsewhere. I.E. in a SAP-Installation it is under /oracle/client/92x_64/... and the SAP-Kernel is using this path correctly when the Environment is specified.
Are you sure, your SHLIBPATH Environment is adopted correctly ?

Volker

[Arunvijai_4]

Hi Shiv,

While compiling or building an application, we should give the path where it should be installed, some thing like for Secure shell,
It should be, --prefix=/opt/ssh and for Internet express products, it is --prefix=/opt/iexpress/

This path will get embed into binaries and when you install other than default path, it wouldn't get the correct configuration files, libraries, etc.. etc..

So, we always give a softlink to the default path.

Hope this is clear.

-Arun

[Steven E. Protter]

Shalom Shiv,

You can do this, but there is no real reason.

If you set the ORACLE_HOME variable in setup to this non-standard location and the other ORA variables, everything is going to work exactly as it should.

Choosing to softlink may be more work.

You could however softlink in place of a directory and then you need not alter the ORA variables.

Its kind of a choice. Most oracle DBA's are gong to do a env | grep ORA to see where oracle is if they need to know this.

As probably stated above where Oracle looks for binaries is totally dependent on the environment variables.

SEP