If you are not a user of the USGS-maintained Swarm application, commonly used in the Earthworm community, please disregard this message.
Over the last few years usage of Swarm to repeatedly poll the IRIS DMC’s web services for near real-time data has grown significantly despite our request that users not employ this pattern of usage in our guidelines. Currently, the Swarm application is responsible for approximately 75% of the hits, between 8 and 10 million daily, to our fdsnws-dataselect web service interface. Theses requests result in less than 1/2 of a percent the daily shipment from that web service. The resources used to service these requests, from a relatively few number of users, has reached the point where it is adversely effecting usage by others. To protect the limited resources of the DMC for use by a broad range of users, starting November 20th the DMC will not be servicing requests by Swarm for time series data via web services.
As stated in the guidelines, the DMC’s SeedLink service is the appropriate service to use for accessing near real-time data in a streaming fashion. In 2013 IRIS Data Services funded ISTI to develop the addition of SeedLink support in Swarm. We encourage Swarm users to switch to this mode of usage before November 20th.