Application Delivery (ADX)

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Occasional Contributor
Posts: 17
Registered: ‎11-10-2010

Cache’s traffic drop when connection reaches the maximum threshold

Dear All,

In the earlier software version 12.2.01, we had many problem related to Persistent Hash and almost is fixed in latest version 12.2.01b. After testing with newest software version, I’ve got another problem that traffic drop when connection reached the maximum threshold. Please see figure below:

Figure-1

ReachMaxConnTrafficDrop.jpg

Configuration

server cache-name cs70 110.164.253.70

max-conn 40000

weight 6

port http

port http url "HEAD /"

port http group-id  10 10

!

server cache-name cs71 110.164.253.71

max-conn 40000

weight 4

port http

port http url "HEAD /"

port http group-id  10 10

!

I’m not sure what wrong with it (or ServerIron handles connection before forwarding to Cache Server?) Is this normal behavior?

Beat Regards,

Tony

Occasional Contributor
Posts: 11
Registered: ‎06-29-2009

Re: Cache’s traffic drop when connection reaches the maximum threshold

Hi Tony,

From the snippet is not clear if you were using L4 or L7 TCS.

Also, where was the traffic drop seen?

Salvo

Occasional Contributor
Posts: 17
Registered: ‎11-10-2010

Re: Cache’s traffic drop when connection reaches the maximum threshold

Hi Salvo,

Please see the Figure-1 in earlier post. You'll see graph (from SwiftCache)

  • I used URL hashing in this environment like command below (my understanding it should be L7)

..

default hash-persist url search-url "" offset 0 length 80

..

  • When I started routing prefix (using route-map) to ServerIron, connection dramatically increase and remains the same close to the maximum threshold (max-conn).
  • Until traffic reach the maximum threshold (I use "logging consol" and terminal monitor command and kept an eye on syslog), connection slightly decrease as shown in Figure-1 before slightly increasing in 15 minutes (during traffic decreasing client can reach the internet without any effect).

Tony

Occasional Contributor
Posts: 11
Registered: ‎06-29-2009

Re: Cache’s traffic drop when connection reaches the maximum threshold

Hi Tony,

Without traffic analsysis is not easy to tell you what exaclty happened and in which sequence; however do keep in mind that when L7 TCS is introduced HTTP1.1 clients will be forced to use HTTP 1.0.

This is very likely to be the reason for you to see the number of connection increasing on the cache servers.

Salvo

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