Archive for March, 2014

CDN Request Pipelining

March 16, 2014

Not all Content Delivery Networks (CDN) request pipeline (also known as Pre Caching System).

Request pipelining is a technique to reduce the number of origin hits for simultaneous requests. If there are three simultaneous requests for a non cached item then one server will make the request to the origin and the other two servers will wait until the server making its request has completed and then return the cached content.

The impact of having no request pipelining depends on the nature of what your origin is serving. If origin hits are particularly heavy CPU/IO wise and/or you have flash traffic (large amount in very short window) then you will definitely want your CDN to request pipeline.

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Not all CDN providers cache on first request

March 16, 2014

It’s not something CDN (Content Delivery Network) providers broadcast but not all CDNs cache an object on first request. Their rationale being they don’t want to fill their cache with items that are not frequently requested.

The impact of don’t cache on first request really depends on the nature of what your origin is serving. If origin hits are particularly heavy CPU/IO wise and/or you have flash traffic (large amount in very short window) then you will definitely want your CDN to cache on first request.

The good news is many CDNs can turn this off so first requests are cached.

Amazon introduce rudimentary CloudFront reporting and ELB logging

March 14, 2014

At long last Amazon have introduced rudimentary CloudFront reporting and ELB logging.

No longer do you have to write scripts to download and process thousands of log files from S3 or use third party services to get basic CloudFront reports. Although if you need anything more advanced than these, which is quite likely, you will

  • Number of Requests: show the number of HTTP or HTTPS requests served by edge locations in the selected region for the specified CloudFront distribution.
  • Data Transferred: show the total amount of data transferred over HTTP or HTTPS from CloudFront
  • Data Transferred from CloudFront Edge Locations to Your Users: This chart shows data transferred from CloudFront edge locations in the selected region to users, combining both HTTP and HTTPS usage.
  • Data Transferred from CloudFront to Your Origin: This chart shows data transferred from CloudFront edge locations in the selected region to your origin for POST, PUT PATCH, OPTIONS, and DELETE methods, again combining both HTTP and HTTPS.