On Mon, Oct 11, 2010 at 9:53 AM, Henry Luo <h...@choicestream.com> wrote: > We have an application that does a lot of updates to the rows. We use > replication factor of 3 and are moving to multiple data centers. We would > like to accomplish the following setup: > > > > Data are replicated to other data centers. RackAwareStrategy seems to be > able to handle that, however > > > > 1) We don’t need the data replicated across data centers for each > individual update, since they got overridden a lot. Rather, we’d like it be > replicated ‘once a while’, say after x number of updates to a row, or after > y number of minutes. In essence, it’s a delayed write of the latest copy > only to remote nodes. > > 2) We would like the read be handled only by the nodes local to the > client, i.e., don’t bother to send read requests to the remote data center > since it’s too slow. If the request fails locally, just let it fail. > > > > Is there a way to accomplish this by > > 1) Configure Cassandra in a certain way > > 2) Change/Add replication strategy > > 3) Change/Add some core Cassandra features > > 4) Use another layer in front of Cassandra – I’d rather not to go this > route. > > > > Thanks. > > > > Henry > > > > ________________________________ > The information transmitted is intended only for the person or entity to > which it is addressed and may contain confidential, proprietary, and/or > privileged material. Any review, retransmission, dissemination or other use > of, or taking of any action in reliance upon this information by persons or > entities other than the intended recipient is prohibited. If you received > this in error, please contact the sender and delete the material from all > computers. >
1) No you can not do this. In 7.0 you can set the read_repair_chance to a low % so read repairs only happen periodically. 2) If you have your multi-data center configuration setup properly with respect to snitches, and you read at Consistency Level ONE, or DCQuorum, and set read_repair_chance to a low % as specified above you will achieve this. Edward
