Re: iSCSI: Login Redirect

[Caitlin Bestler <cait@asomi.com>]

On Tuesday, July 15, 2003, gilligan@intransa.com wrote:

>Hi - If you are using redirect to implement fault
>tolerance/load balancing as we sketched out in
>draft-gilligan-iscsi-fault-tolerance-00.txt, there may be
>transients when an initiator gets  redirected multiple times. 
>For example, say A redirects the initiator to B.  But say B has
>more recent information about the actual location of the
>target, so it redirects the initiator to C.  Eventually A
>learns the same information as B and then redirects initiators
>directly to C.  So the initiator should be prepared to accept
>some number of consecutive redirects.
>
>Of course, if the redirection goes on indefinitely or loops - say A 
>redirects to B, which redirects to C, which redirects to A, etc. - that 
>probably does represent either a configuration error or a bug.  So the 
>initiator may wish to detect a redirection loop or an excessive number 
>of  redirections.
>
>But, as you point out, what represents "excessive redirection"
>is in the eye of the initiator.  So, I don't think that the
>main iSCSI spec needs to call out a specific hard limit.
>

In order to cover the type of fault-tolerance scenario you cited
wouldn't it make sense to set a minimum that the initiator SHOULD
be willing to accept?

That way cluster builders would have a base that they could assume
would not result in iniator failures (only delays).