Hot backups

James Miller jimm at
Fri Nov 14 11:58:36 EST 2003

> On Fri, 14 Nov 2003, Rob Siemborski wrote:
> > On Fri, 14 Nov 2003, Simon Matter wrote:
> >
> > > IIRC taking a snapshot with LVM/XFS takes just a few seconds. I guess
> > > everything should continue after the snapshot. What do the cyrus
> > > do if they receive SIGSTOP? Will they stop immediately or will they
> > > stop at all? I mean, if a process receives SIGSTOP while it writes to
> > > file, will the write finish before the process stops?
> >
> > I'm pretty sure if you just stop the processes where they are, you'll
> > still get an inconsistent store.  (E.g. the mail file is written out,
> > the index files aren't yet updated).
> As I think about this further -- it might be possible to somehow signal to
> all of the cyrus processes that they need to reach a quiescent state, but
> I suspect that doing this to the point of absolute consistency may be
> significantly time consuming, as you may find yourself waiting for network
> operations to complete also.
> I don't think the work to even get to that point is trivial however.

Hi all,

Rob, I'm still abit confused about what's needed to get cyrus (including
index files) into a consistent state -- ready for a backup/snapshot.. etc.


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