I've been working with the Oracle RDBMS for a few years and today, after installing one for the n-th time, I was left wondering, why do we install it in /u01, /u02, etc.?

Of course you could install it somewhere else, but for some unknown reason, this convention is used everywhere and I haven't seen any serious Oracle installation in, for example, /opt

Any history lesson I missed?

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    download.oracle.com/docs/html/A97297_01/appg_ofa.htm. What was confusing in this document? Can you be more specific in your question. The document seems clear, what confused you? – S.Lott May 27 '11 at 16:39
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    I believe the question is about the etymology of the directory name – Codebling May 27 '11 at 16:55
  • @Code Bling: The document seems quite clear on that point. What more does one need to know? – S.Lott May 27 '11 at 17:25
  • @S.Lott: you're right. You probably could have answered instead of commenting too – Codebling May 27 '11 at 17:55
  • @Code Bling: I don't know what the answer should be because I don't understand the question. I'm hoping that @Ubersoldat clarifies the question by listing something that was confusing or hard to understand. Then I think the question can be answered. – S.Lott May 27 '11 at 17:56

It is based upon very old unix and VMS. In the early 80s when unix (i.e. Sun Solaris) machines were first coming on line, there were no standards as to how or where to mount your drives other than the root one. So you needed something that was easy to type (i.e. short), identified which physical drive it was (for when it died). With oracle, each mounted drive was used for one datafile which was never accessed by anything other than Oracle. Early versions of Oracle had limitations on the length of the paths for their data files. Plus you (the dba) needed to use command line tools and edlin to fix configuration files so Oracle could find it's data files after a drive died.

To sum up, for Oracle 6 and 7, you wanted short, easy to remember drive paths which mapped to physical drives for quickness of maintenance.

Since that time, standards have been created, modified, management tools added. But that documentation has never been changed. Because it works as described. And smart DBAs can figure out how it works in their systems. And if they can't Oracle Consulting (at $2K per day per head) will be more than happy to do it for you.

  • I also like @jlliagre pointing at a more POSIX path. – Eldelshell May 29 '11 at 12:27
  • AFAIK, there is still no standard location for permanent file systems mount points. /u01 still seem to me a good choice almost guaranteed not to clash with future standard. – jlliagre May 29 '11 at 15:43

According to the document S Lott points to, /u01 is the recommended standard name for "User data mount point 1". I guess it has been chosen instead of something like /opt/oracle/user01 to save some space and keystrokes.

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