It is impossible to write based on disk in the system.
So we’re going to upgrade from a memcached bucket to an ephemeral bucket rather than a couchbase bucket.
Are there posts that compare the performance of memcached buckets and ephemeral buckets?
I looked it up, but I couldn’t find it.
(A comparison between the couchbase and the ephemeral bucket was found, but not with the memcached bucket.)
I’ve seen benchmarks that show ephemeral buckets with 7x or more throughput over memcached buckets for a GET workload. Unfortunately I don’t see any published details and these were run when the new bucket type was first introduced, so it may be slightly different now. I would still fully expect your workload to benefit from this move. It’s worth noting that we announced with Couchbase Server 6.5 that memcached buckets are deprecated and would recommend that ephemeral buckets are used in preference as we will phase out memcached buckets from Couchbase Server in a future release.
Ian McCloy (Principal Product Manager, Couchbase)
Further to what Ian said, our internal tests have shown that Ephemeral buckets can significantly outperform memcached buckets. Unfortunately we don’t have any official numbers that we can publish at the moment.
In addition to the expected performance increase, moving to an Ephemeral bucket provides access to the many key features that Couchbase is renowned for, such as XDCR, N1QL Queries, and Mobile Sync. See here for a comparison of bucket capabilities.