Technical data

84 ServerIron ADX Advanced Server Load Balancing Guide

53-1002435-03

Cache persistence using URL hashing

ServerIronADX(config-csw-p1)# match r1 forward 1

ServerIronADX(config-csw-p1)# match r1 hash-persist url search-url “v=” offset 0

length 16

Parsing the host string

Parsing the host string allows you to select a “pattern-string” within a URL to determine a starting

point for identifying a URL sting to perform hashing on. This pattern string is combined with a

configured offset value to identify a starting point. From this starting point in the URL, a string that

will be used for hashing is derived by a method that is specified by the options you select for the

hash-persist url search-host command. These options are described in the following.

Parsing using the “pattern string” only – With this option, the ServerIron ADX begins at the starting

point in the URL and includes all of the characters up-to the end of the host string to form the string

used for hashing.

Search host string by starting at a “pattern string” and ending at a delimiter – With this option, the

ServerIron ADX begins at the starting point in the URL and includes all of the characters up-to a

specified delimiter character in the host string to form the string used for hashing.

Search host string by starting at a “pattern string” and continuing for a specified length – With this

option, the ServerIron ADX begins at the starting point in the URL and includes the number of

characters specified to form the string used for hashing.

Parsing using the “pattern string” only

The following example identifies a pattern string to perform hashing on with an offset of “0”.

NOTE

Because hash-persist action is a secondary action, you must add a forward action as shown in the

following example, before adding a hash-persist action.

ServerIronADX(config)# csw-policy p1

ServerIronADX(config-csw-p1)# match r1 forward 1

ServerIronADX(config-csw-p1)# match r1 hash-persist url search-host “www.” offset

Syntax: [no] hash-persist url search-url <pattern-string> offset <offset-value>

The contents of the <pattern-string> variable string are used with this command to define the

starting place in the hash string portion of the URL string. If the url string has multiple such pattern

strings, only the first one will be used. If the pattern string is not found, the system will abort the

rest of searching steps, and choose the default hashing method. If the pattern string is found, the

TABLE 7 Results for parsing the entire URL by method

Method String used for hashing

pattern string only bUfp24dwzOA&playnext=1&videos=XA7MyzKoQXQ&feature=featured

pattern string with a

delimiter of “&”

cbUfp24dwzOA

pattern string with a

length value of “16”

bUfp24dwzOA&play