Pool Redirect

That looks about right. Is the portion of the URI always the same length? ie, are your pool names pool_SAMPLE1, pool_SAMPLE2, etc? If so, you can change the command to:

set pool_string [string toupper [string range [HTTP::path] 1 7]]

You can test the string range command using a simplified test rule:

when RULE_INIT {
    Save a test path
   set ::path "/sample1/path/to/file.ext"
    Starting with the / as positiion 0, parse the path
   set ::pool_string [string toupper [string range $::path 1 7]]
   log local0. "\$::pool_string: $::pool_string"
}

Here is the sample output from /var/log/ltm:

Rule : $::pool_string: SAMPLE1

Once you get that working, you can use the same command in the normal iRule. Just replace the test variable $::path with [HTTP::path].

set pool_string [string toupper [string range [HTTP::path] 1 7]]

Aaron