On 1 March 2017 at 07:23, al so <volks...@gmail.com> wrote: > How would the data get repaired then? i.e. looking for complete list of > Cons when AAE is Off. > > On Tue, Feb 28, 2017 at 9:45 AM, Alexander Sicular <sicul...@basho.com> > wrote: > >> Right. AAE does not come for free. It consumes disk, memory and CPU. >> Depending on your circumstances it may or may not be advantageous for your >> system. >> >> On Tue, Feb 28, 2017 at 11:39 Matthew Von-Maszewski <matth...@basho.com> >> wrote: >> >>> Performance gains on write intensive applications. >>> >>> > On Feb 28, 2017, at 11:18 AM, al so <volks...@gmail.com> wrote: >>> > >>> > Why would anyone disable AAE in riak 2.x? >>> >> There are several mechanisms in Riak that repair data. AAE [0] is intended to detect corrupted data that is not regularly accessed in other ways. When objects are read, the read-repair mechanism [1] will also fix up lost or corrupted data. Finally, if a partition is lost and AAE is not enabled, you can perform a manual partition repair operation [2].
So, if your use case involves short-lived data, or data that is regularly read or updated, turning off AAE may allow the cluster to handle a higher peak load. However, there are several cases where having AAE enabled is important. These include the use of Riak Search / Yokozuna, which without AAE will not be able to detect objects missing or not yet deleted from a Riak core under high load, and AAE based MDC replication. Overall, leaving AAE turned on is recommended for most use cases, but you should give the cluster enough resources to handle the maximum expected load while also doing IO and CPU intensive AAE operations like AAE tree rebuilds. Kind Regards, Magnus [0]: https://docs.basho.com/riak/kv/2.2.0/learn/concepts/active-anti-entropy/ [1]: https://docs.basho.com/riak/kv/2.2.0/learn/concepts/replication/#read-repair [2]: https://docs.basho.com/riak/kv/2.2.0/using/repair-recovery/repairs/#repairing-partitions -- Magnus Kessler Client Services Engineer Basho Technologies Limited Registered Office - 8 Lincoln’s Inn Fields London WC2A 3BP Reg 07970431
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