online moving mailbox to a different partition
brong at fastmail.fm
Mon Oct 31 17:16:16 EDT 2011
On Mon, Oct 31, 2011 at 01:58:01PM -0700, Andrew Morgan wrote:
> On Mon, 31 Oct 2011, Martin Kraus wrote:
> > hi. I have several hundred gigs of mail messages on a partition and I'd
> > like to move it to a different partition but copying takes a very long
> > time and I don't want to have such a long downtime. I was wondering if
> > the renamemailbox command moves a whole mailbox to a different cyrus
> > partition online including the whole mailbox hierarchy?
> If I remember correctly, Cyrus will lock the mailbox while it moves it. I
> try to do mailbox moves during low usage times, but I don't bother
> scheduling an outage for it. I've never had any users complain.
Honestly, replication is much nicer than anything else for this! I
wonder if we could use the replication engine to do partition moves
locally. Basically, it does three passes - so the final moment in
which the lock is required is very short - there is very little data
to transfer, and all the files required are hot in cache.
For a rename within a single filesystem there's less clear value in
the idea - you're bargaining on the links taking a long enough time
to justify the multiple rewrites of the cyrus.index rather than
just copying the files over.
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