HAST: question about secondary outage time

Pawel Jakub Dawidek pjd at FreeBSD.org
Tue Apr 20 23:49:04 UTC 2010


On Tue, Apr 20, 2010 at 10:45:40PM +0200, Lorenzo Perone wrote:
> 
> Hello,
> 
> Welcome to HAST in 8/stable! Happy to see it around.
> 
> The manual states..:
> 
> >When primary hastd is unable to connect or connection fails,
> >it will try to re-establish connection every few seconds.
> >Once connection is established, primary hastd will synchronize
> >every extent that was modified during connection outage
> >to the secondary hastd.
> 
> Question: For how long can a secondary be offline before a
> full synchronisation becomes necessary? In other words, on which 
> resources and/or tunables does this depend upon?

There is no threshold that will trigger full synchronization. If
secondary if offline even for a very long time, but primary wasn't
modified much during that time, it will take very short while to sync.
Full synchronization if only performed when clean provider is connected
or in unlikely situation when every extent becomes dirty during
secondary outage.

> Great work pjd, I guess we're all big fans of all your GEOMs, and this 
> is a welcome new one :)

Thank you.

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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