[infinispan-dev] x-site: taking a site offline automatically

[Mircea Markus]

On 26 Sep 2012, at 08:28, Bela Ban wrote:

> Hi Mircea,
> 
> I think we need a 3rd option in addition to a retry interval and a 
> number of attempts, to take a site offline: a min-time (or whatever we 
> want to call it).
> 
> Say we have retry-interval=1000 and maxRetries=5. This means that if we 
> get a SITE-UNREACHABLE 5 times for a given site, we declare that site 
> offline and cease sending requests to it.
> 
> However, if we have 5 different threads sending requests to the site, 
> then each of them will increment the counter and thus we take the site 
> offline after 1 second !
+1, well spotted!

> That's where min-time comes in: we should wait at least min-time until 
> we take any site offline, even if maxRetries has been exceeded.
> 
> Example: min-time=60000 (ms), maxRetries=10, retryInterval=1000 (ms)
We don't have a built in retry mechanism, are you referring to the one in jgroups?
Or to add a retry mechanism for xsite operations as well?
> 
> If we have 20 threads sending requests to site SFO (which is down), then 
> we might have numRetries=20 after 10 seconds, and perhaps numRetries=60 
> after 50 seconds. But only once 60 seconds have elapsed do we take SFO 
> offline.
> 
> The main reason for min-time would be to prevent taking a site offline 
> during a short period of time when the site master changes and multiple 
> threads incrementing numRetries in short order.
> 
+1
> -- 
> Bela Ban, JGroups lead (http://www.jgroups.org)
> _______________________________________________
> infinispan-dev mailing list
> infinispan-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/infinispan-dev

Cheers,
-- 
Mircea Markus
Infinispan lead (www.infinispan.org)




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