Idan,

Actually in the case you described of using a 3 node Riak cluster with n_val of 2 the behavior you see makes perfect sense. When using only three nodes Riak does not guarantee that all replicas of an object will be on distinct physical nodes. So if you have one node down you can hit a case where both of the replicas of an object stored in Riak live on the downed node. This explains the reason you see occasional failure to retrieve an object with s3cmd, but most of the time it works just fine. It is for this reason we strongly recommend people to use at least 5 nodes in their production deployments. For testing, using at least use 4 nodes in the cluster will likely reduce the chances of this situation occurring versus using only 3.

Also just be very cautious about reducing the n_val to 2. You will save on storage space doing that, but there is a trade-off to be made in availability and performance in doing so. 

Hope that helps shed some light. 

Kelly

On August 22, 2013 at 10:12:06 AM, Idan Shinberg ([email protected]) wrote:
Thanks for the aid

This is a testing environemt . no-one accesses it aside of me

Prior to creating the objects via riak-cs , I set the cluster to n_val 2 for the default bucket props .
On that empty cluster , i started creating objects . ( around 500) .
Then I stopped and killed one of the nodes . 
Then the issues mentioned above were seen.

still doesn't make any  sense...

Regards,

Idan Shinberg


System Architect

Idomoo Ltd.

 

Mob +972.54.562.2072

email [email protected]

web www.idomoo.com

Description: file:///Users/kelly/Library/Containers/it.bloop.airmail/Data/Library/Application Support/Airmail/General/Local/1377192732334581760/Attachments/fc66336e-e750-4c2d-b6e3-985d5a06b...@idomoo.co.il


<<attachment: image001.jpg>>

_______________________________________________
riak-users mailing list
[email protected]
http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com

Reply via email to