Do you need partial object caching?

Partial object caching (POC) is part of our large file optimization support. It increases origin server offload by caching in chunks, instead of as a single, composite object.

POC is required for the delivery of "large files"—those in excess of 10 MB in size. It's automatically enabled if you select any of these large files options for your Origin Object Size.

  • 10-100MB.
  • Greater than 100 MB.
  • Unknown. POC is applied for an object that is greater than 10 MB in size, if the object falls into what you've selected for Content Type. For example, if you've selected "Software" as your Content Type, POC is enabled if a file of that type is requested that's over 10MB in size.

If you set too small a file size, POC is not be enabled for these larger files, and 403 errors may be returned for requests.

If you select a large files setting, but your origin never actually serves files in that size range, the Akamai platform makes additional requests to the origin. This can impact overall performance and access. This happens because the edge server requests the first byte of each object to determine if the minimum object size criteria (at least 10MB) has been met. Once that check fails, the server simply re-requests the entire object from the origin.

What should I do?

We recommend that you verify the size of your delivery objects on your origin, and select the appropriate size to ensure that POC is enabled or disabled, as necessary.

If you're not sure of your file sizes, or can't verify them, set Origin Object Size to "Unknown." Akamai will still apply basic best practices settings to optimize delivery.