irule feature question

You can also change the mask for LDNS persistence on GTM to /16, and that should keep the mega proxies from bouncing around. Of course YMMV, since all other LDNS are subject to the same grouping.

But if you have to deal with it @ LTM, assuming the pools have different names, I think you could do that with a class and an iRule cross-referencing poolname to target virtual. I'd say it would have to collect & hold the request until after the pool is selected & then decide what to do with it:

class xPoolname2VSName {
  PoolA  serverA.domain.com
  PoolB  serverB.domain.com
  PoolC  serverC.domain.com
}

when HTTP_REQUEST {
  set CookiePool [findstr [HTTP::cookie names] "BIGipServer" 11 " "]
  if { $CookiePool !=""}{
    set clength [HTTP::header Content-Length]
    if { [HTTP::header Content-Length] > 1048576 
      set clength [HTTP::header Content-Length]
    } else {
      set clength 1048576
    }
    set uri [HTTP::uri]
    HTTP::collect $clength
  }
}
when LB_SELECTED
  if { $CookiePool != "" && \
    $CookiePool != [LB::server pool]}{
    set VSName [findclass $CookiePool $::xPoolname2VSName " "]
    if $VSName != ""}{
      HTTP::redirect "http://$VSName/$uri
    }
  } else {
    HTTP::release
  }
[

HTH

/deb