ReiserFS and general cyrus filesystem usage information - was Re: best filesystem for imap server

[Andreas Hasenack]

On Thu, Dec 02, 2004 at 09:20:20PM -0200, Henrique de Moraes Holschuh wrote:
> As a first example (and just like you said), if you don't get the DB_CONFIG
> stuff exactly right, you can get anything from lock ups to environment
> corruption.  This is quite easy to hit with OpenLDAP.  From what you wrote,

Indeed, openldap's defaults are wrong. In fact, it uses BDB's defaults which
are just wrong for openldap. The openldap developers prefer to have the admin
change it.

> I guess subversion will also get hit by this one if DB_CONFIG is not
> optimal for your dataset.

Not necessarily, it may set some parameters itself. Our DB_CONFIG file, though, was
shipped with subversion at least.

> Second, it is prone to behave badly in non-trivial workloads on non-trivial
> apps on non-trivial (i.e. not UP) boxes.  Which is exactly the kind of thing
> you have on any big Cyrus or OpenLDAP deployment.  I have some hopes that

Also in our subversion deployment, but it behaves quite nicely. Commit and checkout
times are good.

> the very latest 4.2 fixes this.  I *do* know the others didn't, since I've
> experienced the crashes myself.
> 
> BDB 4.x is a complex piece of software, and it shows.

It is complex indeed. I like to say it has many buttons to turn or press.

> > It's heavily used by openldap and subversion. We, for example, have a
> 
> And at least with openldap, it causes a lot of trouble.

Without a properly tuned DB_CONFIG file, I agree. And the issue of why openldap
needs one (and doesn't set some basic values, like a bigger than miserable 32kbytes
log buffer) escapes me.

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