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On 2017-10-13 03:37 AM, Julien Danjou wrote:
> On Fri, Oct 13 2017, Yaguang Tang wrote:
> 
>> I see the latest Gnocchi support using Redis as a storage backend, I am
>> testing performance of Redis and Ceph, it seems using Redis as storage
>> backend we can achieve  more realtime metric
>> data, gnocchi status shows there is always few metric to process.
>>
>> Is Redis a recommend storage backend ?
> 
> Redis is recommended as an incoming measures backend, not really as a
> storage – though it really depends on the size of your installation.
> 
> Up until 4.0 version, Gnocchi process metrics every
> $metricd.metric_processing_delay seconds. With version 4.1 (to be
> released), the Redis incoming driver has a more realtime processing
> delay which avoids having to poll for incoming data.
> 

what Julien said :)

redis as a storage driver really depends on how you setup persistence[1] 
and how much you trust it[2].

would love to see your redis vs ceph numbers compared to mine[3] :)

[1] https://redis.io/topics/persistence
[2] https://aphyr.com/posts/283-jepsen-redis
[3] https://medium.com/@gord.chung/gnocchi-4-introspective-a83055e99776 
(tested part of 4.1 optimisations)

cheers,

-- 
gord