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  • This is extremely useful if you wish to download big amounts of data.
  • Efficiency tips:
    • Smaller Nr of tapes (a request accesses) means better request efficiency.
    • Requests for data which is online in general go faster
    • Ideally requests should not access more than 1 tape.
  • Please read the retrieval efficiency pages
  • Please also read why MARS activity is important

Why MARS activity is important?



(smile) MARS activity  is important for many  reasons:

  • It can give you a good insight of your current request status and of your request details (like Nr of fields, Nr of tapes accessed etc)
  • It can give you a very good indication of why your request is slow
  • It can provide you a lot of information that you need to improve the efficiency of your request like
    • how many tapes your request is accessing (in the MARS log output)
    • the reason why a requests is queued.
    • other users requests.
  • etc
titleOther users requests

(lightbulb)Many requests submitted by other users may be running in parallel consuming the services resources (MARS slots, Web-API slots, Tapes access slots etc). These requests may be very useful  to understand the efficiency factors.

  • Compare the activity of your requests to the other users activity using the  MARS activity page.
  • See the reason that some requests are "queued" and how long they have been "queued".
  • Have a look on the MARS logs about limitations like:
    • "In marsod-core, the total number of Requests from ECMWF Web API with 1 tape mount [source] is limited to 6"
    • etc


  • There is no limitation on the number of request that a user can submit on our servers.
  • However to improve the Quality of Service the maximum number of active requests per user has been limited to 3
  • You can check the status of all your requests in your job list
  • You can check your active requests in MARS Activity.

Is there any limitation in a single Web-API request?