[ome-devel] cluster support

[Jeremy Muhlich]

On Thu, 2006-11-23 at 14:22 -0500, Ilya Goldberg wrote:
> So the way the OME cluster is set up is that every node is running  
> Apache.  The master node issues requests that include remote DB  
> connection info and job info.  The worker node establishes a DB  
> connection, returns an OK message (to unblock the master), then  
> continues processing the request.  When its done, its supposed to  
> issue an IPC message using the DB driver, but this bit hasn't been  
> working well recently.  Anyway, the master doesn't wait around  
> forever for the IPC "finished" message, so things continue cranking  
> along fairly well.  The only effect seems to be that the master gets  
> loaded a little more than it should be.

Hmmm.  This is a shared cluster with time-limited job queues.  For
example the 15m queue has the highest priority but will kill your job
after 15 minutes.  The complete list of queues in priority order is 15m,
2h, 12h, 1d, 7d, and unlimited.  It could be difficult to employ your
apache-everywhere scheme on this sort of system.  However, a group who
contributes a node gets top priority on it, so that might be the way to
go.

> >
> > Also, is the image server more cpu bound or I/O bound?
> 
> Definitely IO bound.  It could start hitting the CPU if you request  
> lots and lots of rendered planes rather than raw data for analysis,  
> but its probably IO bound even then.

Thanks, that's helpful to know.


 -- Jeremy