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From:Michael Widenius Date:September 2 1999 9:43pm
Subject:Question about Symbolic Links?
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>>>>> "John" == John N Alegre <listhub@stripped>
> writes:

John> Hi.
John> The documentation is a little sparse on the use of links.  In the same section
John> it appears to say you can and you cannot.

John> Here is what I am trying to do.

John> I have MySQL installed on a RedHat system.  Since the /var directory is on the
John> root partition which is not very large.  I want to put the DBs on a different
John> partition and create a link in the /var/lib/mysql dir to the DBs on another
John> partition.

John> First question.  Does the symbolic link have to be on the files i.e. .ISM,
John> .ISD, and .frm files, or can I make a sym link to a directory on a separate
John> partition?

Both will work.  It's however better to use a symbolic link on the directory.

John> OK, another question.  We are working on various additions to Servlet Engines
John> running under different Web Servers.  To do this we have an internal JAZ drive
John> with Linux installed on many JAZ carts and we boot from the JAZ drive to have
John> environments that are different with respect to Web Server, Servlet Engine,
John> etc.  Now the partition that I wish to put the DBs on on the internal HD, as
John> mentioned above, is mounted by all these JAZ / Linux systems.  Can I now make a
John> sym link from these other systems to the DB and have the data intact between
John> systems?  So all systems would sym link to the same DB.  Only one system would
John> be serving the DB at any one time.  MySQL (same version) would be installed on
John> all systems.

You will get problems with updating if your OS doesn't support file
locks properly (MySQL uses fcntl() locks to handle external locks).
If you only do reads then you will not have any problem.

Note however that in most cases it's much faster to have on dedicated
database server than to try to let many computers access the same databases

Question about Symbolic Links?John N. Alegre2 Sep
  • Question about Symbolic Links?Michael Widenius3 Sep
  • Re: Question about Symbolic Links?Jules Bean3 Sep