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