Hi all,
sorry for this being a bit late (but since it is before CR1 it is not that late :), but the XSite config looks a bit redundant and we should improve it a bit before release

<global>
  ...
  <sites
        local="LON"/>
  ...
</global>

Since this just provides the local logical name for this site I would instead use

<global>
  ...
  <site
        name="LON"/>
  ...
</global>

In the cache declaration we have the following:

<sites>

<backups backupSites="NYC,SFO">

<backup site="NYC" backupFailurePolicy="WARN" strategy="SYNC" timeout="12000"/>

<backup site="SFO" backupFailurePolicy="IGNORE" strategy="ASYNC"/>

<backup site="LON" strategy="SYNC"/>

</backups>

</sites>

Instead of dumping a list inside an XML attribute (backupSites), can't we just skip that attribute and add an enabled attribute to each backup element ? Also the "backup" prefix to the failure policy is redundant and can be dropped altogether.
Also, while I understand the rationale behind giving a "home element" to all xsite-related configurations (<sites>), I do feel it is unnecessary, so I suggest:

<backups>

<backup site="NYC" failurePolicy="WARN" strategy="SYNC" timeout="12000" enabled="true"/>

<backup site="SFO" failurePolicy="IGNORE" strategy="ASYNC"


        enabled="true"/>

<backup site="LON" strategy="SYNC" enabled="false"/>

</backups>

This means that <backupFor/> also moves as a direct child element of a cache declaration.

Just my 2¢

Tristan