[isapros] Array Member Failover
- From: "Jason Jones" <Jason.Jones@xxxxxxxxxxxxxxxxx>
- To: <isapros@xxxxxxxxxxxxx>
- Date: Thu, 25 May 2006 22:44:22 +0100
Hope this question is not too low brow, if so, kick me and I will move
it to isaserver.org for the masses to mull over ;-)
Anyhow, has anything changed with array member failover behavior in EE
with ISA2k4 SP2? I am sure I have never had problems with array member
failovers in the past...
I have recently deployed an SP2 array with several members and while
testing I have noticed that if the server listed as the first entry
defined within the wpad.dat file is unavailable then the browser delays
for quite some time before attempting to connect to other array members
(e.g. working through the server list in the wpad.dat file). It does
seem to get there, but we're talking 20 seconds or so per website. Once
the website is loaded, performance is fine. When using a new URL, the
delays appears again.
Apart from failover, balancing and distr caching seems to be working
well. I know I could be using NLB, but I believe the following to be
good practice:
Web Proxy => Autoconfig script (client side CARP)
FW Client => RR DNS
I am using a generic name of customerarray.domain.com with RR DNS
entries to balance autoconfig requests between array members. This is
the name used in the autoconfig URL.
I know NLB may come to mind as a workaround, but it is hard to implement
as the customer is using NIC teaming at the hardware driver level to
aggregate NICS and provide NIC fault tolerance. NLB and NIC teaming
never play well from what I have experienced :-(
Can someone please define normal behavior for a client that is using an
autoconfig script when array members are unavailable? I kinda get the
feeling the problem is with the browser and not the array, but not
totally sure when IE does with the script in terms of processing...
I've tried looking at wpad.dat caching and caching of bad proxies, but
neither seems to make much difference...
Any ideas?
JJ
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