autofs-5.0.3 - update replicated server selection documentation

From: Ian Kent <raven@themaw.net>

Update the replicated server selection README documentation to

reflect the selection rules now used.

---

 CHANGELOG                |    1 +

 README.replicated-server |   53 ++++++++++++++++++++++------------------------

 2 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG

index af3318a..be39e33 100644

--- a/CHANGELOG

+++ b/CHANGELOG

@@ -31,6 +31,7 @@

   umount during expire.

 - make mount of multi-mounts wuth a root offset atomic.

 - add replicated server selection debug logging.

+- update replicated server selection documentation.

 14/01/2008 autofs-5.0.3

 -----------------------

diff --git a/README.replicated-server b/README.replicated-server

index 333dea3..1d771d3 100644

--- a/README.replicated-server

+++ b/README.replicated-server

@@ -3,48 +3,45 @@ Supported forms for mount paths are:

 Normal single-host (these are unchanged)

 <path> host:/path/path

+Single host entries are not probed for a server response.

+

 Multiple replicated hosts, same path:

 <path> host1,host2,hostn:/path/path

-This will do an initial RPC call with a .1 second timeout to all hosts to 

-find best match.  If this fails, it will try a 10 second timeout, if this 

-fails it takes the first host.

-

 Multiple hosts, some with same path, some with another

 <path> host1,host2:/blah host3:/some/other/path

-Works as expected

-

 Multiple replicated hosts, different (potentially) paths:

 <path> host1:/path/pathA host2:/path/pathB

-Same as above with RPC calls..

-

 Mutliple weighted, replicated hosts same path:

-

 <path> host1(5),host2(6),host3(1):/path/path

-Will pick lowest weighted host that responds to RPC call.  

-RPC time is not counted, only whether the call got a reply 

-at all.  Initially does a .1 second timeout, if all hosts 

-fail this, moves to 10 second timeout.  If one of the hosts

-is localhost, the automounter will choose that regardless of

-its weight.  (This has been done to remain compatible with

-Sun's automounter)

-

 Multiple weighted, replicated hosts different (potentially) 

 paths:

 <path> host1(3):/path/pathA host2(5):/path/pathB

-Same as above with RPC calls/weighting.

-

-Anything else is questionable and unsupported, but these 

-variations will also work:

-<path> host1(3),host:/blah

-

-Unsupported and I don't know why you would use this, but will 

-work.  Weighted host always gets precedence if it responds to RPC

-

-Anything else, I ain't making no promises.

+For these formats a priority ordered list of hosts is created by using

+the following selection rules.

+

+1) Highest priority in selection is proximity.

+   Proximity, in order of precedence is:

+     - PROXIMITY_LOCAL, host corresponds to a local interface.

+     - PROXIMITY_SUBNET, host is located in a subnet reachable

+       through a local interface.

+     - PROXIMITY_NETWORK, host is located in a network reachable

+       through a local interface.

+     - PROXIMITY_OTHER, host is on a network not directlty

+       reachable through a local interface.

+  

+2) NFS version and protocol is selected by caclculating the largest

+   number of hosts supporting an NFS version and protocol that

+   have the closest proximity. These hosts are added to the list

+   in response time order. Hosts may have a corresponding weight

+   which essentially increases response time and so influences the

+   host order.

+  

+3) Hosts at further proximity that support the selected NFS version

+   and protocol are also added to the list in response time order as

+   in 2 above.

-Jason