Re: [pcp] pmclusterd versus other solutions

[Nathan Scott <nathans@xxxxxxxxxx>]

Hi Jeff,

----- Original Message -----
> > This is the daemon that aggregates indoms for per-cluster-node CPU
> > data on the head node, so
> [...]
> See the emails from 11 August on Debugging sigpipe in pmda.
> 
> But the real problem is that although pmclusterd exposes some 100 metrics or
> so but only 20 of them are actually able to be fetched.
> 

I expect the problem will be due to latency in the polling of remote cluster
nodes, which IIRC is done in a serial fashion (one node after the other IOW)
so one slow-reponding node will affect timeliness of all values?

A design which did the remote fetching in parallel would be better suited,
if so.  You could go with a model where multiple processes fetch then write
metrics using MMV(5) format - see also mmv_stats_init(3) - so a new PMDA may
not be needed at all.

cheers.

--
Nathan