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<p class=MsoNormal>Tahoe Devs,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Is there currently any mechanism, or any plans to implement
a mechanism, which allows for storage nodes to be ‘arranged’ with
nearby gateway/WAPI nodes, allowing for a more logical scaleout in a formal datacenter
environment? To borrow from Hadoop terminology, this would be called ‘Rack
Awareness’ (<a
href="http://hadoop.apache.org/common/docs/r0.17.2/hdfs_user_guide.html#Rack+Awareness">http://hadoop.apache.org/common/docs/r0.17.2/hdfs_user_guide.html#Rack+Awareness</a>).<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>For example, say that I have three facilities, and I wish to
setup 3-4 nodes in each of them in a 3-of-10 scheme:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Facility 1 (ISDN):<o:p></o:p></p>
<p class=MsoNormal>Gateway 1<o:p></o:p></p>
<p class=MsoNormal>Node 1A<o:p></o:p></p>
<p class=MsoNormal>Node 1B<o:p></o:p></p>
<p class=MsoNormal>Node 1C<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Facility 2 (ISDN):<o:p></o:p></p>
<p class=MsoNormal>Gateway 2<o:p></o:p></p>
<p class=MsoNormal>Node 2A<o:p></o:p></p>
<p class=MsoNormal>Node 2B<o:p></o:p></p>
<p class=MsoNormal>Node 2C<o:p></o:p></p>
<p class=MsoNormal>Node 2D<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Facility 3 (56K):<o:p></o:p></p>
<p class=MsoNormal>Gateway 3<o:p></o:p></p>
<p class=MsoNormal>Node 3A<o:p></o:p></p>
<p class=MsoNormal>Node 3B<o:p></o:p></p>
<p class=MsoNormal>Node 3C<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>For arguments sake, let us say that we have a very
expensive, limited connection between these facilities (to make this extreme,
let’s call it a dialup-ish connection – obviously this is an
exaggeration, but the argument scales up).<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>If gateway 1 attempts to retrieve a file, it is obviously
most efficient for it to do so utilizing nodes 1ABC. In the event that 1C
is down, any of the other shares can obviously step in, at a greater cost to
the infrastructure. Ideally, you would also be able to weight the next
best share – if facilities 1 and 2 have ISDN lines, and 3 has a dialup
line, it is preferable for a gateway at facility 1 to query a node at facility
2. If no weighting is configured, or in a distributed friendnet, other possible
methods could be distance vector routing (how many hops to the other nodes with
shares), latency, or Geo-IP lookups.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Best Regards,<o:p></o:p></p>
<p class=MsoNormal>Nathan Eisenberg<o:p></o:p></p>
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