Open Stack

On Fri, Oct 25, 2013, Michael Still <mikal at stillhq.com> wrote:
> On Fri, Oct 25, 2013 at 8:19 AM, Johannes Erdfelt <johannes at erdfelt.com> wrote:
> > On Fri, Oct 25, 2013, Michael Still <mikal at stillhq.com> wrote:
> 
> >> However, when I run it with medium sized (30 million instances)
> >> databases, the change does cause a 10 minute downtime. I don't
> >> personally think the change is worth such a large outage, but perhaps
> >> everyone else disagrees.
> >
> > I'm not sure how you could have 30 million instances. That's a lot of
> > hardware! :)
> 
> This has come up a couple of times on this thread, so I want to
> reinforce -- that database is a real user database. There are users
> out there _right_now_ with 30 million rows in their instance tables
> and using nova quite happily. Now, not all those instances are
> _running_, but they're still in the table.

Why no pruning?

The easiest way to reduce the amount of time migrations take to run is
to reduce the amount of rows that need to be migrated.

The amount of unnecessary data in tables has been steadily increasing.
I'm looking at you reservations table.

JE