[OpenAFS] DB servers seperate from fileservers

John Hascall john@iastate.edu
Mon, 07 Aug 2006 08:33:38 CDT

> John Hascall <john@iastate.edu> wrote:
> >> This means that, during about 10 days, DB servers with 2 different
> >> versions of OpenAFS will have to cohabit (1 x 1.4.1 and 2 x 1.2.13,
> >> then 2 x 1.4.1 and 1 x 1.2.13, before the final 3 x 1.4.1).

> > I suspect it will work.  None the less it sounds like you
> > have put fileservers on your DB servers.  This is really
> > not ideal.

> Why not?  I too run fileservers on AFS DB servers.

  1) Stability.  The uptime of our DB servers is years,
     we can only dream of that for our fileservers.

  2) Restart speed.  Waiting for a pile of disk to
     fsck to get your DB servers up and running again
     is suboptimal.

  3) Load. A busy fileserver on the same machine as your
     DB server can slow your whole cell.

  4) Simplicity.  When something is amiss with a machine,
     the less things a machine is doing, the less things
     to check and the less likely it is the result of
     some wierd interaction.

Reasons for joining them would be (in my mind):

  1) Cost.  Fewer machines == Less cost
     (however, you can easily run the DB servers
      low-cost, even hand-me-down boxes).

  2) Space, power, cooling.  Either you have these or you don't.

  3) You got a really small cell, so it doesn't matter.