sitcky persistence regardless of whether members offline

Hi,

I wrote the iRule below and I'll appreciate if anyone can tell me if have another and/or better way to do that.

I have an case which the communication needs to be persisted with source address regardless of the member becomes offline. This is due to the client access can't start a new session on another server in certain period.

By default persistence, the Big-IP will always send connections to the available server, so I need to discard this option. I also tried to setup the monitoring up time, but it was not very effective.

As the persistence record is cleared when load balance fails, I use the table command.

Does anyone know of a better way to do this?

when RULE_INIT {
    set ::debug_enabled 1
    set ::persist_table "source_addr_sticky_uie"
    set ::persist_timeout 1800
}
when CLIENT_ACCEPTED priority 300 {
    persist virtual server
    set persist_key "[IP::local_addr]:[TCP::local_port]:[IP::remote_addr]"
    set persist_record [table lookup -subtable $::persist_table -notouch $persist_key]
    if { $::debug_enabled } { log local0. "===> persist_key: $persist_key / persist_record: $persist_record" }
    if { $persist_record ne "" } {
        if { [lsearch [active_members -list [LB::server pool]] $persist_record] ne -1 } {
            pool [LB::server pool] member [lindex $persist_record 0] [lindex $persist_record 1]
            table lookup -subtable $::persist_table $persist_key
            if { $::debug_enabled } { log local0. "===> Selecting pool member $persist_record / persist_key: $persist_key" }
            if { $::debug_enabled } { log local0. "===> Updated timeout record table $persist_key" }
        } else {
            reject
            if { $::debug_enabled } { log local0. "===> Failed to select pool member $persist_record / persist_key: $persist_key" }
        }
        if { $::debug_enabled } {
            log local0. "===> Dump table: $::persist_table"
            foreach key [table keys -subtable $::persist_table -notouch] {
                log local0. "===> ${::persist_table}, ${key}, [table timeout -subtable $::persist_table -remaining $key]"
            }
        }
    }
    unset -nocomplain persist_record
}
when LB_SELECTED priority 300 {
    table add -subtable $::persist_table $persist_key [list [LB::server addr] [LB::server port]] $::persist_timeout
    if { $::debug_enabled } { log local0. "=======> Member selected [LB::server addr]:[LB::server port] / persist_key $persist_key" }
}
when LB_FAILED  priority 300 {
    LB::detach
    reject
    if { $::debug_enabled } { 
        if { [info exists persist_key] && [info exists persist_record] } {
            log local0. "===> Fail to select member $persist_record / persist_key: $persist_key"
        }
    }
}