The "High Replication Datastore" (HRD) for App Engine today completed its one year. A year back on January 5, Google launched the HRD for App Engine, that provides the highest level of availability for reads and writes, at the cost of increased latency for writes and changes in consistency guarantees in the API.
"Still transactional, still massively scalable, still fully managed, still running on Google's world-class infrastructure, but with the ability to withstand multiple datacenter outages and no planned downtime!," said Google.
Throughout all this, HRD has had no system-wide downtime (planned or unplanned) and has grown to serve over 3 billion requests per day. Needless to say it's been a phenomenal year.
In a Jan 5 blog post, Max Ross, Datastore Tech Lead highlights the achivements and improvements made to the platform writes, "in Nov 2011, App Engine came out of preview and added a 99.95% SLA for HRD applications."
Adding he said int the recent most release they have launched an updated version of HRD migration tool that ties the duration of the read-only period to your write-rate, rather than the size of your dataset. This makes your migration quick, simple, and easy to plan for regardless of how much data you have. One App Engine customer recently migrated over 500G of Datastore data with only a 10 minute read-only period!
"We realize that moving data requires planning, testing, coordination, and a strong stomach. However, we believe strongly that HRD provides a fundamentally better service than Master/Slave, and we encourage all our customers to migrate to HRD. Over the coming months you can expect to see further improvements to our migration tools (Blob migrations are on the way!), more HRD-only features like Full Text Search, and of course, more 9s than you can shake a stick at," added Ross.