maas-devel team mailing list archive

[John Meinel <john@xxxxxxxxxxxxxxxxx>]

On Oct 19, 2012 8:50 AM, "Julian Edwards" <julian.edwards@xxxxxxxxxxxxx>
wrote:
>
> On Thursday 18 Oct 2012 21:58:59 John Arbash Meinel wrote:

> On Thursday 18 Oct 2012 21:58:59 John Arbash Meinel wrote:
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> > On 10/18/2012 6:00 PM, Francis J. Lacoste wrote:
> > > On 12-10-17 05:02 AM, John Arbash Meinel wrote:
> > >> 18 nodegroups, each nodegroup has 4,000 nodes for 72,000 total
> > >> nodes. Each node has a ~25kB XML string associated with it.
> > >
> > > The 1 cluster controller can host 4k nodes is an assumption we
> > > haven't empirically validated.
> > >
> > > We should probably either validate it, or try variation on the the
> > > number of nodes to clusters ratio (say with 500 per node, 1000,
> > > 2000), just to see how the scaling behave differently.
>
> We've based the 4k on references (which I don't have to hand) that indicate
> that broadcast traffic and DHCP server performance becomes problematic at
> that
> level.  (Having said that, in a case study with a customer whose name I
> cannot
> mention here had 5k nodes with one DHCP server on a flat network)
>
> So we should treat it as an advised maxmium and recommend that the real
> maximum will depend on your networking usage.
>
> > I'll poke one more time, but being able to say "rebuilding tags from 1
> > Region Controller to 20 Cluster Controllers" is network bandwidth
> > bound, rather than CPU bound or DB load bound is a pretty good place
> > to be.
>
> Is rebuilding all tags at once across all machines a realistic scenario?  I
> would have thought that a more likely one is the introduction of a new rack
> (or racks) containing a few nodes at a time.
>
> Cheers.
>