[Mulgara-dev] [Topaz-dev] unable to restore live database from backup

[Life is hard, and then you die]

On Tue, Apr 15, 2008 at 04:37:30PM +0200, Russell Uman wrote:
[snip]
> >>> there's no guarantee that doing an rsync on a running server will give
> >>> you something valid,
> >>
> >> http://docs.mulgara.org/overview/index.html#o1034
> >>
> >> i read this as guaranteeing that i can take a copy from a running server 
> >> (more or less simulating a power outage) and get a consistent set of 
> >> data. am i mistaken?
> > 
> > Yes. That's a common misunderstanding (and this applies to any other
> > db too, including sql db's). Let's take an example: let's say the db
[snip]
>  > I don't think you actually need to take things down - you could just
>  > get an lvm snapshot of the running system, though you'll have to
>  > "recover" that. I wouldn't recommend for normal operations, but for
>  > getting a snapshot of production in order to, say, run some tests on
>  > it should be fine.
> 
> i'll still try to find a time to make a copy with the database down, and 
> to make an itql backup so that i have something recent that i can 
> recover from if necessary. i suspect that the copy will fail, but home 
> the itql backup will work...

As detailed in the other email by Paul, a SIGSTOP/lvm-snapshot/SIGCONT
should work.

> how do you recover?

It's automatic - you'll just see a bunch of warnings during startup
about things not having been closed cleanly.


  Cheers,

  Ronald