horms at verge
Feb 27, 2012, 2:48 PM
On Mon, Feb 27, 2012 at 10:32:16AM -0500, Khosrow Ebrahimpour wrote:
> Hi Krishna,
> On Monday, February 27, 2012 08:08:13 am krishna prasad wrote:
> > Dear All,
> > If the director is configured with Source Hashing scheduling algorithm,
> > the connections are distributed among the back end real servers through
> > looking up a statically assigned hash table by their source IP addresses.
> > My question here is the key for the load balancing is the source IP alone
> > or source IP plus port?
> I haven't used SH scheduling myself, but according to this article
> http://kb.linuxvirtualserver.org/wiki/Source_Hashing_Scheduling only the
> source IP is used.
Yes, the SH scheduler only makes use of the source IP address and
conversely the DH scheduler only makes use of the destination IP address.
> Although I am curious why the hash wouldn't use source IP + Port. Otherwise,
> clients coming from behind a NAT or proxy will all end up on the same
I believe that the motivation for the DH scheduler was for use with
load-balanced caching proxy servers. The SH scheduler is intended
to be used in place of persistence in some situations where it is
desirable to scheduler the same client to the same real-server.
Clearly the presence of NAT can potentially result in a poor result
when using SH. Likewise with persistence, which can provide some
of the same behaviour.
With regards to SH hashing on both the Source IP and port, I'm unclear
of when this would be useful in place of for example WLC
Please read the documentation before posting - it's available at:
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