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Re: slapd, bdb, 32-bit -> 64-bit

On Monday 16 October 2006 09:56, Frode Nordahl wrote:
> On 16. okt. 2006, at 03.08, matthew sporleder wrote:
> >> > And you can definitely add new replicas without causing any
> >>
> >> downtime
> >>
> >> > by using the strategy you're suggesting- even using slapcat/
> >>
> >> slapadd.
> >>
> >> Yes, this would be possible, but as the slapadd step may take several
> >> hours I cannot rely on this. I have tested it with slapadd -q and it
> >> still takes too long. There just is alot of data that must go in
> >> there :-)
> >
> > Use the same binary set on all of your replicas, otherwise you can't
> > reasonably expect the same database files to work.
> There is nothing in Berkeley DB that prevents you from doing this,
> hence the question. But I have learned that it is a deliberate
> decision behind this not working, and I am content with knowing that.
> > I also have a large database (my slapcat-ed file is over 4gb), but I
> > don't see how it's more reliable to shutdown a spare for one hour
> > while you scp versus four hours while you slapadd.  What's the
> > difference?  A minute's worth of replication to catch-up with?
> I would have to take the slave down to do the slapcat as well,

No, you can slapcat while the slave is running.

> and I 
> guess the time difference between slapcat and tar of the binary files
> is next to nil.
> The whole point for having the spare slave is to take it down at the
> same time as I add a new replica to the master servers configuration.
> That way the slapcat / binary copy will be in a good state, and the
> replication will start at the right spot.
> As soon as the slapcat or binary copy is done the replication can
> start on the slave again.
> I can probably evade this by using syncrepl instead?

Yes, if you're using sync-repl, there is no need for this. Take any valid 
snapshot of the database, slapadd on the consumer, start it up, and it will 
catch up. Or, if you can wait a little bit longer, skip the whole 
slapcat/slapadd step entirely.


Buchan Milne
ISP Systems Specialist - Monitoring/Authentication Team Leader

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