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CDN vs S3

jdorfman.posthaven.com

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Re: CDN vs S3

#21

Post by jcampbell1 »

v13inc wrote: post #19
jcampbell1 wrote: post #14

Earlier quoted context omitted.

I am in the process of abandoning Cloudfront, because they have a serious bug when serving video files. They serve HTTP 206 (Range-Get) as HTTP 1.0 but 206 didn't exist in HTTP 1.0. Chrome and Firefox treat this as "uncacheable", thus media assets bypass the local media cache. Depending on the nature of the content, Cloudfront is not usable for video, particularly the kind where people seek around a bunch, like instr…

Why would Cloudfront cause the player to stop buffering the video? Does it happen with a HTTP Download distribution, or the RTMP streaming distribution? I've used both CloudFront and Akamai for serving video, and I don't remember running into those issues. I have only tested it with normal HTTP Download distributions, however.

Cloudfront serves an invalid HTTP response, thus Chrome/Firefox refuse to cache the data. The theory is, it is better to not risk caching bad data. Chrome will still play the video served from Cloudfront, but it wont write any of the data to the media cache. Thus when you pause and buffer, it will only buffer a few seconds of video in the current playback window. It never writes to the cache so buffering must stop.

To see this in action, play a video with chrome://media-internals/ open.

A video served from S3 will get saved to the media cache, and the full video can buffer when paused. A video served from cloudfront will only buffer a few seconds of video.

Update:

It is probably just easier to see for yourself:

Here is a video served from S3. Pause the video in chrome, and you will see the whole video gets buffered:

http://s3.amazonaws.com/jctest20080526/test/test.mp4

Here is the same video served from Cloudfront. Start the video, and pause it, and notice how it doesn't buffer more than a few seconds:

http://d3oocspv43fsel.cloudfront.net/test/test.mp4

Re: CDN vs S3

#22

Post by MichaelApproved »

I was using S3 to deliver secure signed downloads to customers. It worked well enough for a long time but eventually customers started having major connectivity issues and dead slow downloads.

I switched to CliudFront and, of course, downloads improved dramatically. I had to go with CF because we needed signed downloads. Would be nice to have alternatives but I'm happy with CF.

Re: CDN vs S3

#23

Post by philip1209 »

geoffhill wrote: post #11

Amazon Web Services does offer a worldwide CDN, CloudFront. http://aws.amazon.com/cloudfront/

Cloudfront doesn't offer some services that I find necessary, such as nested directory indices (e.g. example.com/folder/ instead of example.com/folder/index.html) and it doesn't return a 404 header on missing pages. I just emailed MaxCDN to see if they provide these.

Re: CDN vs S3

#24

Post by alinajaf »

> I think S3 is a great origin server for static assets

Pro-tip: If you're using Rails, just create a distribution with your app as the origin server and in production.rb, set your asset host to your distributions host. You get the asset cache without having to do the precompile step. Tastes great with Heroku.

Re: CDN vs S3

#25

Post by v13inc »

jcampbell1 wrote: post #21
v13inc wrote: post #19

Earlier quoted context omitted.

Why would Cloudfront cause the player to stop buffering the video? Does it happen with a HTTP Download distribution, or the RTMP streaming distribution? I've used both CloudFront and Akamai for serving video, and I don't remember running into those issues. I have only tested it with normal HTTP Download distributions, however.

Cloudfront serves an invalid HTTP response, thus Chrome/Firefox refuse to cache the data. The theory is, it is better to not risk caching bad data. Chrome will still play the video served from Cloudfront, but it wont write any of the data to the media cache. Thus when you pause and buffer, it will only buffer a few seconds of video in the current playback window. It never writes to the cache so buffering must stop. T…

Thanks for the info, thats very informative. Can you recommend any CDNs that work well with online video? It would be great to find one that is as easy to configure as cloudfront that doesn't have this issue.

I'm not a big fan of Akamai's control panel -- setting up new distributions is way to complicated (albeit more flexible), and configuration changes were taking almost a day to propogate.

Re: CDN vs S3

#26

Post by Icer5k »

philip1209 wrote: post #23
geoffhill wrote: post #11

Amazon Web Services does offer a worldwide CDN, CloudFront. http://aws.amazon.com/cloudfront/

Cloudfront doesn't offer some services that I find necessary, such as nested directory indices (e.g. example.com/folder/ instead of example.com/folder/index.html) and it doesn't return a 404 header on missing pages. I just emailed MaxCDN to see if they provide these.

Cloudfront as a CDN supports directory indexes and 404s, it's just S3 that doesn't. If you point a CF distribution at your own server with directory indexes enabled, CF will send those through to the user.

Re: CDN vs S3

#27

Post by Icer5k »

True, S3 is not a CDN, but for a lot of use cases, serving directly from S3 is fine.

Taking Vine for example, I picked a random vine from twitter (https://vine.co/v/bE3YI365gxd) and a popular vine from twitter (https://vine.co/v/bEFFxdwjK9x). The popular video and thumbnails are served from a CDN, where the new one with no traffic is served directly from S3.

YouTube did the same thing in it's early days. CDNs are not required for all traffic, and blindly recommending them is a bad prescient. They're really great for content that is frequently accessed, but their value greatly decreases on long-tail content.

Re: CDN vs S3

#28

Post by mathrawka »

jdorfman wrote: post #5
davidandgoliath wrote: post #4

Earlier quoted context omitted.

You also seem to have ignored it in your post, any reason you didn't test cloudfront?

@davidandgoliath I work for MaxCDN so I would probably get fired. =P

So you post something that basically compares apples and oranges? Honestly, this post turns me off from MaxCDN.

Re: CDN vs S3

#29

Post by modemuser »

jcampbell1 wrote: post #14
jcastro wrote: post #12

Since this thread will likely turn into people asking about Cloudfront performance, does anyone have any real-world experience with CloudFront vs. Rackspace with Akamai CDN? On paper the Rackspace one looks like a great performance/price alternative.

I am in the process of abandoning Cloudfront, because they have a serious bug when serving video files. They serve HTTP 206 (Range-Get) as HTTP 1.0 but 206 didn't exist in HTTP 1.0. Chrome and Firefox treat this as "uncacheable", thus media assets bypass the local media cache. Depending on the nature of the content, Cloudfront is not usable for video, particularly the kind where people seek around a bunch, like instr…

> HTTP 1.0

If that is the only problem, flipping one bit in every response seems like a really simple solution. Why hasn't Cloudfront fixed it yet, do they know about this?

Re: CDN vs S3

#30

Post by jcampbell1 »

v13inc wrote: post #25
jcampbell1 wrote: post #21

Earlier quoted context omitted.

Cloudfront serves an invalid HTTP response, thus Chrome/Firefox refuse to cache the data. The theory is, it is better to not risk caching bad data. Chrome will still play the video served from Cloudfront, but it wont write any of the data to the media cache. Thus when you pause and buffer, it will only buffer a few seconds of video in the current playback window. It never writes to the cache so buffering must stop. T…

Thanks for the info, thats very informative. Can you recommend any CDNs that work well with online video? It would be great to find one that is as easy to configure as cloudfront that doesn't have this issue. I'm not a big fan of Akamai's control panel -- setting up new distributions is way to complicated (albeit more flexible), and configuration changes were taking almost a day to propogate.

I haven't had the time to find another vendor, thus can't recommend one.

Amazon promised a fix, but then back tracked. Their explanation was something along the lines of "an old version of Squid has the same problem, thus it is okay". I cannot comprehend the logic system they employ to think that is a good reason to live with the bug.

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