We use Redis Cluster quite extensively. The one thing to be very cautious and load test if running in a cloud environment is failover of nodes that are very loaded in terms of keys. If your nodes are holding multiple GBs of data, and depending on your persistence and other configuration settings, Redis may need to hit the disk to recover. If you don't have enough IOPS provisioned, be prepared for a long recovery time. The other thing that used to be problem but is getting much better now is the maturity of the different client libraries with respect to handling Redis Cluster specific idiosyncrasies.
I just got back from RedisConf and antirez brought up the idea (or that it's already in-development... he was not clear) of releasing an official redis cluster proxy for use with older/less-featured clients.
I believe it was brought up in the keynote (which I missed unfortunately), and also as part of one of the Redis Clients talks.
Interesting. At which point is this recovery a problem? Id assume it would only be recovering on the slave since there will have been a newly promoted master after failover?
