[tahoe-lafs-trac-stream] [tahoe-lafs] #648: collect server capacities and put them on the welcome page, output of 'df' for SFTP, etc.

[tahoe-lafs]

#648: collect server capacities and put them on the welcome page, output of 'df'
for SFTP, etc.
-------------------------+-------------------------------------------------
     Reporter:  zooko    |      Owner:
         Type:           |     Status:  new
  enhancement            |  Milestone:  undecided
     Priority:  major    |    Version:  1.3.0
    Component:  code-    |   Keywords:  introducer usability statistics
  frontend-web           |  ostrom
   Resolution:           |
Launchpad Bug:           |
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Comment (by zooko):

 #1206 (node status page does not indicate per server if it is taking
 shares) was a duplicate of this. In that ticket, gdt wrote:

  A very important indicator of the health of a server in a grid is whether
 it will take new shares. A client node has enough information (or could
 record it) to know this. It should show somehow if a node is not taking
 shares (either if it says it won't or if it actually doesn't). The lack of
 this feature makes it almost impossible to assess if files can be uploaded
 without trying it.

 Whether a server is accepting shares is determined like this: if the
 server is configured to be in read-only mode then it sets its "available
 space" to 0:
 [source:trunk/src/allmydata/storage/server.py?annotate=blame&rev=4895#L189
 StorageServer.get_available_space()]. If "reserved space" is set then it
 subtracts that much space from its available space:
 [source:trunk/src/allmydata/storage/server.py?annotate=blame&rev=4895#L71
 StorageServer.__init__()]. It includes the resulting "available space" in
 the metadata about itself that it sends back in response to
 {{{get_version}}} requests:
 [source:trunk/src/allmydata/storage/server.py?annotate=blame&rev=4895#L203
 StorageServer.remote_get_version()].

 The client invokes {{{get_version}}} on each server as soon as it connects
 to that server, but it doesn't do so ever again as long as it stays
 connected:
 [source:trunk/src/allmydata/storage_client.py?annotate=blame&rev=5018#L232
 storage_client.NativeStorageServer].

 So, this ticket is basically a superset of #1206. The client is already
 learning (once, at connection establishment time) how much space the
 server is offering, which is equal to 0 if and only if the server is
 either in read-only mode or is full. If the client would display this
 information to the user in a nice comprehensible way then both #1206 and
 this ticket would be fixed.

 {{{patch-needed}}}! :-)

-- 
Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/648#comment:15>
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