Module 4 - Refreshing Content in Akamai

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Dec 8, 2013 (3 years and 11 months ago)

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Module 4
-

Refreshing Content in Akamai
Server Caches

©
2011
Akamai

Powering a Better Internet

Objectives

After completing this module, you will be able to:


identify the mechanisms available to refresh your content cached
in Akamai edge servers.


use the tools that Akamai provides to refresh content.


plan for origin downtime.


©
2011
Akamai

Powering a Better Internet

When
a client request is made,
Akamai
edge
servers contact
the
origin under the following circumstances:


When the requested objects are not in cache


If the requested object is marked as no store


It the time to live or TTL of the object has expired


Introduction

©
2011
Akamai

Powering a Better Internet

Cache Refreshing Mechanisms

To manually refresh content and not wait for TTL expiration, Akamai
provides two basic mechanisms:

1.
Purge
-

based

2.
Invalidation
-

based

©
2011
Akamai

Powering a Better Internet

Purge
-
based Mechanisms


On purging content from the Akamai network, edge servers will re
-
retrieve content from the origin on the next request.


The Akamai edge server:


removes
the object from
cache.


on the next request, sends
a full
HTTP
GET request to the
origin to fetch
objects.


r
efreshes
the cache with
fresh content.




©
2011
Akamai

Powering a Better Internet

Invalidation
-
based Mechanisms


Invalidation
-
based mechanisms cause Akamai edge servers to re
-
validate the freshness of content with an IMS GET on the next
client request.


On receiving a client request, edge servers:


send an IMS Get request to the origin to fetch objects.


remove and replace cached object only if newer version is
available




©
2011
Akamai

Powering a Better Internet

Tools to Refresh Content

Akamai provides these tools on Akamai EdgeControl to purge and
invalidate content:

1.
Content
Control
Utility (CCU)

2.
Enhanced
Content Control
Utility (ECCU)




©
2011
Akamai

Powering a Better Internet

Content Control Utility


Allows
you to specify the objects to remove from cache by URL,
ARL,
or by CP Code
.


Benefits:


Easy
to
use interface


Requests
can be removal or invalidation
based


Provides the
option of receiving email
notifications
of the result
of your refresh
actions


Disadvantage: You
must specify each object to be removed
;
you
cannot specify a directory by
wildcard.

©
2011
Akamai

Powering a Better Internet

Accessing the CCU

©
2011
Akamai

Powering a Better Internet

Using the CCU

©
2011
Akamai

Powering a Better Internet

Using the CCU (Cont…)

©
2011
Akamai

Powering a Better Internet

Using the CCU


Purging by CP Code


Be mindful that removing or invalidating all objects under a CP
code can cause high load on your origin server.







©
2011
Akamai

Powering a Better Internet

CCU


Important Points to Remember


Purge
and invalidation
-
based requests
using the CCU take
approximately 10 minutes to take
effect.


Files submitted for CCU requests should not contain more than
100 URLs each less than 400 characters in length.


If you receive a “Request Entity Too Large” error, split your file
into smaller files and try again.


You can submit any number of files containing about 100 URLs,
but there cannot be more than 10,000 outstanding requests at
any one time.


If you receive a Code 332 error, which indicates you have
exceeded this limit, wait for about 10 minutes and try again.





©
2011
Akamai

Powering a Better Internet

Content Control Utility API

The CCU API:


can be used to write programs that submit a list of cached objects
to be removed from the Akamai network.


uses SOAP, HTTP or HTTPS, and either the removal
-
based or
invalidation
-
based refresh method.


is typically used in one of two ways:


to develop a GUI for those who manage Web content, rather
than providing access to Akamai EdgeControl.


to integrate the API into a content management system.





©
2011
Akamai

Powering a Better Internet

Enhanced Content Control Utility


ECCU
provides for invalidation
-
based refresh by rules such as date
or time, path, file extension, or more complex
criteria.


There
are three ways to use
the ECCU
:


As a web interface on
Akamai EdgeControl


File
upload, using a function on
Akamai EdgeControl


ECCU
Publisher or Publish
ECCU

Note:



Invalidation
-
based
refreshing is the only option for refreshing
content if you are using

the ECCU
.


An
invalidation based request will take approximately
30
-
40
minutes to complete.







©
2011
Akamai

Powering a Better Internet

Accessing the ECCU

©
2011
Akamai

Powering a Better Internet

Using the ECCU

©
2011
Akamai

Powering a Better Internet

Comparison of Tools

Tool

Description

CCU

A web page on Akamai EdgeControl

that allows
you to specify objects to remove from cache, or
to remove objects by CP Code.


CCU API

Same as the CCU UI, but a SOAP
-
based API.


ECCU

A web page on Akamai EdgeControl

that allows
you to specify refreshing objects by rules
involving path and file extensions.


ECCU File Upload

Using the ECCU Web UI, you can upload ECCU
files containing rule
-
based instructions beyond
path and extension.


ECCU Publisher

An EdgeControl Web Service SOAP
-
based API
that allows you to upload ECCU files.

©
2011
Akamai

Powering a Better Internet

When to Use the CCU and ECCU

CCU:


For refreshing specific URLs


If there are more than about 10,000 objects,
-

allows you to purge
by CP code

ECCU:


When you can identify objects by directory or file extension.

Important:

Ensure that you update the content on your origin server
before
submitting a content refresh request


©
2011
Akamai

Powering a Better Internet

Lab 5
-

Refreshing Cache