Memcache style buckets don't participate in replication so all keys and values exist on a per node basis. In other words if you have 4 nodes and one goes down you have lost 25% of your cache.
To know which nodes contains the keys /values you want on a per-request basis you need to use a consistent key hash algorithm. The preferred method here is to use moxi as your proxy to the cluster (which I believe just uses a libketama style hashing algorithm) - this maps a key to a particular node. --chad On Wed, Dec 25, 2013 at 2:23 AM, Gregory Taylor <[email protected]> wrote: > I'm thinking about setting up a hosted memcache service using Couchbase, > and am evaluating pain points and looking to get some answers. While I've > read through a good chunk of the documentation, a lot of it seems focused > on the regular Couchbase buckets. I had a few questions about the memcache > bucket types in particular: > - I saw mention that memcache buckets (and their keys) always live on a > single node, unlike couchbase buckets. Is this true? > - For the couchbase buckets, I see "strong consistency" is offered, > though I'm not sure if this applies to memcache buckets (and to what > extent). If my users are connecting via SASL+binary memcache protocol, is > there ever a case where an immediate SET/GET of the same key will result > in > out-of-date values being returned by GET? > - Do I need to point each user at a specific node in the cluster? > Perhaps the one that their bucket resides on? I ask this because of the > statement I saw about memcache buckets living on single nodes, though I am > not sure this was correct or reflects the current state of things. > -- > You received this message because you are subscribed to the Google Groups > "Couchbase" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "Couchbase" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
