[tahoe-dev] Issue with Unplugging One Node from private grid

[Bostonian]

The following is the architecture:

5 storage nodes + 1 introducer node + 1 client node (each of which is
a desktop computer, running ubuntu 10.10)

in the client node,
shares.needed = 3
shares.happy = 4
shares.total = 5

I tested the following two scenarios:

Case 1) stop tahoe in one of the storage nodes

In this case, everything works fine and the stopped storage node shows
disconnected from the gateway.

Case 2) unplug the Ethernet cable in one of the storage nodes

In this case, I can connect to the client node, but cannot create any
dir or download/upload any file. All the nodes still show connected
from the gateway.

Based on these tests, here are my guesses:

i) when stopping tahoe, it pro-actively notifies introducer about its leave.

ii) when unplugging the cable, introducer does not know that one node
leaves. As a result, it still tries to connect it when requests.

This seems to an bug with Tahoe. Given the nature of the system, it
will see this situation quite often. Is there any monitoring mechanism
at introducer?

On Mon, Nov 29, 2010 at 10:05 AM, Shawn Willden <shawn at willden.org> wrote:
> Can you describe the architecture?  How many nodes, where they were located,
> which one you were connecting to and which one was unplugged?
>
> On Mon, Nov 29, 2010 at 10:41 AM, Bostonian <ygwen77 at gmail.com> wrote:
>>
>> Thanks for suggestion. I am sure that one storage node was unplugged.
>> It should be similar as what Myckel suggested. Is there a fix for
>> this? Thanks.
>>
>> Best Regards,
>> Yonggang
>>
>> On Thu, Nov 25, 2010 at 10:43 AM, Myckel Habets <myckel at sdf.lonestar.org>
>> wrote:
>> > Could be the same thing that I saw happening in bug #68.
>> > Pull one storage node out and the gateway still tries to connect to it,
>> > blocking the whole client.
>> >
>> >
>> >> Dear All:
>> >>
>> >> I am experiencing an issue with unplugging one node from my private
>> >> grid. Here is my testbed:
>> >>
>> >> 1) 5 storage nodes
>> >> 2) N=5, K=3
>> >> 3) two clients running on my laptops
>> >>
>> >> It has been working fine for normal operations. Then, I thought it
>> >> should continue to work even if
>> >> I unplug two nodes out of the grid. However, I cannot connect to the
>> >> grid from either of the clients after
>> >> I unplug only one Ethernet cable.
>> >>
>> >> Has anyone else seen similar issue? Thanks.
>> >>
>> >> Best Regards,
>> >> Yonggang
>> >> _______________________________________________
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>> >>
>> >
>> >
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>
>
> --
> Shawn
>
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