Status update on Tahoe LAFS integration with Nextcloud

[brucet]

Jean-Paul et al,

 

I just wanted to give you a status update on the progress I have made on creating a Nextcloud filesystem plugin for Tahoe-LAFS.

 

The good news is that the plugin is fully functional and seems to work quite well with Tahoe LAFS. The plugin maps a either Tahoe URI or a Tahoe alias / path to a Nextcloud mount point. The plugin also detects Tahoe magic-folder configurations and maps the resulting Tahoe magic-folder directory to a Nextcloud mount point. I have tested the plugin using both the Nextcloud web interface and using Nextcloud clients (wabdav). Both interfaces seem to work reliably (with a caveat).

 

The bad news is that I am having intermittent trouble with Tahoe mutable files which I believe are used to hold file directories in the Tahoe filesystem. I have multiple Tahoe groups running right now each with its own introducer. Each Tahoe group has about 8 nodes in it. The nodes which are members of the Tahoe groups are always behind a NAT. I use the frp package (https://github.com/fatedier/frp) to create tunnels to a server with a public IP to get around the NAT issue. The result is that bandwidth between nodes can be reasonable low (< 1Mbps) and RTT can be quite high.

 

What I am finding is that when I use the Tahoe filesystem heavily, the Tahoe client state machine will often hang for about 5 – 10 minutes before some type of timeout occurs and data transfers continue. Here is an example of a Tahoe status screen I see when the Tahoe client state machine is hung:

 

All of the Storage Indexes above are mutable files which I believe hold Tahoe filesystem directories. When a client hangs up, it stays in this state for a significant period of time (5 – 10 minutes) before timing out and continuing on. I have found that once the Tahoe client is in this state, it will not operate properly until I restart the Tahoe node.

 

I have found multiple nodes in my network which exhibit similar behavior.

 

I am looking at the Tahoe code right now to try to understand the details of the mutable files subsystem and what may be causing this issue. Any pointers / feedback would be greatly appreciated.

 

            Bruce T

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