Coda File System

Re: the role of "primary host"

From: <u-codalist-z149_at_aetey.se>
Date: Sat, 2 Aug 2014 01:28:03 +0200
On Fri, Aug 01, 2014 at 02:40:14PM -0400, Jan Harkes wrote:
> Servers have no concept of primary, and a client can decide on a
> different one every time it makes an RPC2 call, but keeping it somewhat
> stable is better because it prevents a client from single handedly
> creating server-server conflicts.
> 
> Every client independently decides who it likes best as a primary host.

Ok.

> > I assume that the servers would go through the resolution properly
> > (if all of them are available) but then which of them will reply to the
> > client and whether the client will be able to make sense of the answer?
> 
> We prefer to call the 'primary host' of a resolution the 'coordinator'
> to avoid this type of confusion. And yes the servers don't care if the
> clients think of them as primary hosts or not, the first thing a
> coordinator does is grab an exclusive lock on the object on all other
> servers to make sure that there is only one coordinator at a time.

Not all details became clear yet but it feels better,
time to return to looking at the source.

Thanks again Jan!

Rune
Received on 2014-08-01 19:28:20