On 3/13/12 1:37 PM, Van Doorn, Jan R wrote:
Hello,
I apologize if this has been discussed before, or is in the
documentation. I am fairly new to ATS, so forgive my ignorance.
I am looking at building a multi tier CDN, and want to have "content
affinity" when my edge caches miss and select a parent cache, meaning, I
want to have multiple caches in the same parent caching location, and I
don't want to have these caches store the same content.
I know I could use ICP to share the caches in a location, but the
records.config says "ICP Configuration. NOTE! ICP is currently broken
NOTE!", and I am hesitant to use ICP, as it seems to bring a lot of
complexity.
Hmmm, ICP wouldn't solve this would it? ICP is generally a multi-cast
protocol, intended to be used from within the colocation. It also duplicates
the cache across all peers of an ICP network. ICP is similar to the
clustering feature that ATS, which is one reason why no one has bothered
with getting ICP to work.
If you intended to do parent proxy across colos (I'm guessing?), you'd want
to use the TSHttpTxnParentProxySet() AP in a plugin. Or, if you can
partition your parent proxies based on various "rules" on the URL (e.g. a
prefix of a path), you can use our parent.config to pick and choose
parent(s) for various URLs (but it's a manually maintained config, obviously).
If really what you are asking is for a distributed cache within the colo
where each object is on one single cache, then take a look at the clustering
feature. It uses URL hashes. It wouldn't work well across colocations though.
-- Leif
