[vox-tech] Is NFS unsafe? [Was: Clusters, renderfarms and MySQL...]

[timriley at appahost.com]

> -------- Original Message --------
> Subject: Re: [vox-tech] Clusters, renderfarms and MySQL, LAN projects
> using more than one Linux at a time
> From: Bill Broadley <bill at broadley.org>
> Date: Mon, March 04, 2013 12:58 pm
> To: lugod's technical discussion forum <vox-tech at lists.lugod.org>
> 

<snip>

> > The only tweak I've needed is to store a 300 million
> > record table
> > on another machine through NFS. And short of a complete backup,
> 
> It's inherently unsafe to use mysql to access tables over NFS.  I guess
> it could be ok if it's read only.

NFS has been an easy way to implement growth and has been reliable in
the
three decades I've been using it.

In Kyle Rankin's (http://www.linuxjournal.com/users/kyle-rankin)
book, "The Official ubuntu Server Book" (copyright 2009,
Pearson Education, Inc.), he dedicates three pages to NFS's setup
and caveats. One caveat is to have the many machines mounting the
exported directory to have the user IDs and group IDs the same for
each user name and group name.
The other caveat is to remember that you cannot use the root
account to change the permissions on an NFS mounted directory.
Instead, you must be logged into the computer that locally has the
directory. He presents NFS as just another of the many tools available
to
system administrators.

The vulnerability presented here is having multiple MySQL servers
accessing the same table across NFS. Of course, don't do that.

<snip>