How Sears Could Have Used the Cloud to Stay Available Black Friday

@Hamish,

 

 

Yes, *she* knows nothing of the internal architecture. Which is why assumptions were made. Because we don't know and even if we did, we wouldn't be sharing that info publicly.

 

 

Yes, many stuff that looks static isn't. However, if you look closely at the Firebug capture you can see that much of the page likely is static. It's rare that CSS and images are dynamically generated.

 

 

Persistent sessions. Ah, yes, persistence. Something we've written a lot about in the past.

 

 

Persistence vs Persistent

 

 

Enabling Session Persistence with iRules

 

 

Session persistence based on source IP

 

 

Affinity|Session Persistence

 

 

BIG-IP doesn't understand session limiting unless you tell it to care about session limiting. Off the top of my head there are two ways to do this:

 

 

1. The app server must be able to indicate that it is reaching session capacity so the BIG-IP can use that information to stop sending it requests. This could be done through monitoring using a page that indicates how many more sessions could be handled, and then BIG-IP can act upon that information.

 

 

2. Using the persistence tables in iRules or an HTTP derived "session specific" statistics profile, you can track the number of sessions on any given server and use that information in determining which servers (if any) are available.

 

 

I'm sure many folks would prefer this functionality be "built in" but it's so variable depending on the configured session length, size of data stored in sessions, etc... that it's not something that's easily abstracted and genericized. Better to allow the customer the ability to specifically configure for their environment than pre-bake a solution that only solves the problem for a few customers.

 

 

Thanks!

 

Lori