Ticket #778: mutabledocsv2.dpatch

Sun May 23 21:28:36 PDT 2010  Kevan Carstensen <kevan@isnotajoke.com>
  * Note that servers of happiness only applies to immutable files for the moment

New patches:

[Note that servers of happiness only applies to immutable files for the moment
Kevan Carstensen <kevan@isnotajoke.com>**20100524042836
 Ignore-this: cf83cac7a2b3ed347ae278c1a7d9a176
] {
hunk ./docs/architecture.txt 186
 files which have been uploaded once before, while making sure we still wind up
 with as many shares as we desire.
 
-If we are unable to place every share that we want, but we still managed to
-place enough shares on enough servers to achieve a condition called "servers of
-happiness" then we'll do the upload anyways. If we cannot achieve "servers of
-happiness", the upload is declared a failure.
+Before a file upload is called successful, it has to pass an upload health
+check. For immutable files, we check to see that a condition called
+'servers-of-happiness' is satisfied. When satisfied, 'servers-of-happiness'
+assures us that enough pieces of the file are distributed across enough
+servers on the grid to ensure that the availability of the file will not be
+affected if a few of those servers later fail. For mutable files and
+directories, we check to see that all of the encoded shares generated during
+the upload process were successfully placed on the grid. This is a weaker
+check than 'servers-of-happiness'; it does not consider any information about
+how the encoded shares are placed on the grid, and cannot detect situations in
+which all or a majority of the encoded shares generated during the upload
+process reside on only one storage server. We hope to extend
+'servers-of-happiness' to mutable files in a future release of Tahoe-LAFS. If,
+at the end of the upload process, the appropriate upload health check fails,
+the upload is considered a failure.
 
 The current defaults use k=3, servers_of_happiness=7, and N=10. N=10 means that
 we'll try to place 10 shares. k=3 means that we need any three shares to
hunk ./docs/architecture.txt 204
-recover the file. servers_of_happiness=7 means that we'll consider the upload
-to be successful if we can place shares on enough servers that there are 7
-different servers, the correct functioning of any k of which guarantee the
-availability of the file.
+recover the file. servers_of_happiness=7 means that we'll consider an immutable
+file upload to be successful if we can place shares on enough servers that
+there are 7 different servers, the correct functioning of any k of which
+guarantee the availability of the immutable file.
 
 N=10 and k=3 means there is a 3.3x expansion factor. On a small grid, you
 should set N about equal to the number of storage servers in your grid; on a
hunk ./docs/configuration.txt 275
  larger than 256, because of the 8-bit erasure-coding algorithm that Tahoe
  uses.
 
- shares.happy allows you control over the distribution of your file. An upload
- is only considered successful if shares are placed on at least 'shares.happy'
- distinct servers, the correct functioning of at least k of which is sufficient
- to guarantee the availability of the uploaded file. This value should not be
- larger than the number of servers on your grid.
+ shares.happy allows you control over the distribution of your immutable file.
+ An upload is only considered successful if shares are placed on at least
+ 'shares.happy' distinct servers, the correct functioning of at least k of
+ which is sufficient to guarantee the availability of the uploaded file. This
+ value should not be larger than the number of servers on your grid.
+
+ (Mutable files use a different share placement algorithm that does not 
+  consider this parameter.)
 
 
 == Storage Server Configuration ==
}

Context:

[setup: remove bundled setuptools_darcs-1.2.8.tar
zooko@zooko.com**20100522015333
 Ignore-this: 378b1964b513ae7fe22bae2d3478285d
 This version of setuptools_darcs had a bug when used on Windows which has been fixed in setuptools_darcs-1.2.9. Hopefully we will not need to bundle a copy of setuptools_darcs-1.2.9 in with Tahoe-LAFS and can instead rely on it to be downloaded from PyPI or bundled in the "tahoe deps" separate tarball.
] 
[tests: fix pyflakes warnings in bench_dirnode.py
zooko@zooko.com**20100521202511
 Ignore-this: f23d55b4ed05e52865032c65a15753c4
] 
[setup: if the string '--reporter=bwverbose-coverage' appears on sys.argv then you need trialcoverage
zooko@zooko.com**20100521122226
 Ignore-this: e760c45dcfb5a43c1dc1e8a27346bdc2
] 
[tests: don't let bench_dirnode.py do stuff and have side-effects at import time (unless __name__ == '__main__')
zooko@zooko.com**20100521122052
 Ignore-this: 96144a412250d9bbb5fccbf83b8753b8
] 
[tests: increase timeout to give François's ARM buildslave a chance to complete the tests
zooko@zooko.com**20100520134526
 Ignore-this: 3dd399fdc8b91149c82b52f955b50833
] 
[run_trial.darcspath
freestorm77@gmail.com**20100510232829
 Ignore-this: 5ebb4df74e9ea8a4bdb22b65373d1ff2
] 
[docs: line-wrap README.txt
zooko@zooko.com**20100518174240
 Ignore-this: 670a02d360df7de51ebdcf4fae752577
] 
[Hush pyflakes warnings
Kevan Carstensen <kevan@isnotajoke.com>**20100515184344
 Ignore-this: fd602c3bba115057770715c36a87b400
] 
[setup: new improved misc/show-tool-versions.py
zooko@zooko.com**20100516050122
 Ignore-this: ce9b1de1b35b07d733e6cf823b66335a
] 
[Improve code coverage of the Tahoe2PeerSelector tests.
Kevan Carstensen <kevan@isnotajoke.com>**20100515032913
 Ignore-this: 793151b63ffa65fdae6915db22d9924a
] 
[Remove a comment that no longer makes sense.
Kevan Carstensen <kevan@isnotajoke.com>**20100514203516
 Ignore-this: 956983c7e7c7e4477215494dfce8f058
] 
[docs: update docs/architecture.txt to more fully and correctly explain the upload procedure
zooko@zooko.com**20100514043458
 Ignore-this: 538b6ea256a49fed837500342092efa3
] 
[Fix up the behavior of #778, per reviewers' comments
Kevan Carstensen <kevan@isnotajoke.com>**20100514004917
 Ignore-this: 9c20b60716125278b5456e8feb396bff
 
   - Make some important utility functions clearer and more thoroughly 
     documented.
   - Assert in upload.servers_of_happiness that the buckets attributes
     of PeerTrackers passed to it are mutually disjoint.
   - Get rid of some silly non-Pythonisms that I didn't see when I first
     wrote these patches.
   - Make sure that should_add_server returns true when queried about a 
     shnum that it doesn't know about yet.
   - Change Tahoe2PeerSelector.preexisting_shares to map a shareid to a set
     of peerids, alter dependencies to deal with that.
   - Remove upload.should_add_servers, because it is no longer necessary
   - Move upload.shares_of_happiness and upload.shares_by_server to a utility
     file.
   - Change some points in Tahoe2PeerSelector.
   - Compute servers_of_happiness using a bipartite matching algorithm that 
     we know is optimal instead of an ad-hoc greedy algorithm that isn't.
   - Change servers_of_happiness to just take a sharemap as an argument,
     change its callers to merge existing_shares and used_peers before 
     calling it.
   - Change an error message in the encoder to be more appropriate for 
     servers of happiness.
   - Clarify the wording of an error message in immutable/upload.py
   - Refactor a happiness failure message to happinessutil.py, and make
     immutable/upload.py and immutable/encode.py use it.
   - Move the word "only" as far to the right as possible in failure 
     messages.
   - Use a better definition of progress during peer selection.
   - Do read-only peer share detection queries in parallel, not sequentially.
   - Clean up logging semantics; print the query statistics whenever an
     upload is unsuccessful, not just in one case.
 
] 
[Alter the error message when an upload fails, per some comments in #778.
Kevan Carstensen <kevan@isnotajoke.com>**20091230210344
 Ignore-this: ba97422b2f9737c46abeb828727beb1
 
 When I first implemented #778, I just altered the error messages to refer to
 servers where they referred to shares. The resulting error messages weren't
 very good. These are a bit better.
] 
[Change "UploadHappinessError" to "UploadUnhappinessError"
Kevan Carstensen <kevan@isnotajoke.com>**20091205043037
 Ignore-this: 236b64ab19836854af4993bb5c1b221a
] 
[Alter the error message returned when peer selection fails
Kevan Carstensen <kevan@isnotajoke.com>**20091123002405
 Ignore-this: b2a7dc163edcab8d9613bfd6907e5166
 
 The Tahoe2PeerSelector returned either NoSharesError or NotEnoughSharesError
 for a variety of error conditions that weren't informatively described by them.
 This patch creates a new error, UploadHappinessError, replaces uses of 
 NoSharesError and NotEnoughSharesError with it, and alters the error message
 raised with the errors to be more in line with the new servers_of_happiness
 behavior. See ticket #834 for more information.
] 
[Eliminate overcounting iof servers_of_happiness in Tahoe2PeerSelector; also reorganize some things.
Kevan Carstensen <kevan@isnotajoke.com>**20091118014542
 Ignore-this: a6cb032cbff74f4f9d4238faebd99868
] 
[Change stray "shares_of_happiness" to "servers_of_happiness"
Kevan Carstensen <kevan@isnotajoke.com>**20091116212459
 Ignore-this: 1c971ba8c3c4d2e7ba9f020577b28b73
] 
[Alter Tahoe2PeerSelector to make sure that it recognizes existing shares on readonly servers, fixing an issue in #778
Kevan Carstensen <kevan@isnotajoke.com>**20091116192805
 Ignore-this: 15289f4d709e03851ed0587b286fd955
] 
[Alter 'immutable/encode.py' and 'immutable/upload.py' to use servers_of_happiness instead of shares_of_happiness.
Kevan Carstensen <kevan@isnotajoke.com>**20091104111222
 Ignore-this: abb3283314820a8bbf9b5d0cbfbb57c8
] 
[Alter the signature of set_shareholders in IEncoder to add a 'servermap' parameter, which gives IEncoders enough information to perform a sane check for servers_of_happiness.
Kevan Carstensen <kevan@isnotajoke.com>**20091104033241
 Ignore-this: b3a6649a8ac66431beca1026a31fed94
] 
[Alter CiphertextDownloader to work with servers_of_happiness
Kevan Carstensen <kevan@isnotajoke.com>**20090924041932
 Ignore-this: e81edccf0308c2d3bedbc4cf217da197
] 
[Revisions of the #778 tests, per reviewers' comments
Kevan Carstensen <kevan@isnotajoke.com>**20100514012542
 Ignore-this: 735bbc7f663dce633caeb3b66a53cf6e
 
 - Fix comments and confusing naming.
 - Add tests for the new error messages suggested by David-Sarah
   and Zooko.
 - Alter existing tests for new error messages.
 - Make sure that the tests continue to work with the trunk.
 - Add a test for a mutual disjointedness assertion that I added to
   upload.servers_of_happiness.
 - Fix the comments to correctly reflect read-onlyness
 - Add a test for an edge case in should_add_server
 - Add an assertion to make sure that share redistribution works as it 
   should
 - Alter tests to work with revised servers_of_happiness semantics
 - Remove tests for should_add_server, since that function no longer exists.
 - Alter tests to know about merge_peers, and to use it before calling 
   servers_of_happiness.
 - Add tests for merge_peers.
 - Add Zooko's puzzles to the tests.
 - Edit encoding tests to expect the new kind of failure message.
 - Edit tests to expect error messages with the word "only" moved as far
   to the right as possible.
 - Extended and cleaned up some helper functions.
 - Changed some tests to call more appropriate helper functions.
 - Added a test for the failing redistribution algorithm
 - Added a test for the progress message
 - Added a test for the upper bound on readonly peer share discovery.
 
] 
[Alter various unit tests to work with the new happy behavior
Kevan Carstensen <kevan@isnotajoke.com>**20100107181325
 Ignore-this: 132032bbf865e63a079f869b663be34a
] 
[Replace "UploadHappinessError" with "UploadUnhappinessError" in tests.
Kevan Carstensen <kevan@isnotajoke.com>**20091205043453
 Ignore-this: 83f4bc50c697d21b5f4e2a4cd91862ca
] 
[Add tests for the behavior described in #834.
Kevan Carstensen <kevan@isnotajoke.com>**20091123012008
 Ignore-this: d8e0aa0f3f7965ce9b5cea843c6d6f9f
] 
[Re-work 'test_upload.py' to be more readable; add more tests for #778
Kevan Carstensen <kevan@isnotajoke.com>**20091116192334
 Ignore-this: 7e8565f92fe51dece5ae28daf442d659
] 
[Test Tahoe2PeerSelector to make sure that it recognizeses existing shares on readonly servers
Kevan Carstensen <kevan@isnotajoke.com>**20091109003735
 Ignore-this: 12f9b4cff5752fca7ed32a6ebcff6446
] 
[Add more tests for comment:53 in ticket #778
Kevan Carstensen <kevan@isnotajoke.com>**20091104112849
 Ignore-this: 3bb2edd299a944cc9586e14d5d83ec8c
] 
[Add a test for upload.shares_by_server
Kevan Carstensen <kevan@isnotajoke.com>**20091104111324
 Ignore-this: f9802e82d6982a93e00f92e0b276f018
] 
[Minor tweak to an existing test -- make the first server read-write, instead of read-only
Kevan Carstensen <kevan@isnotajoke.com>**20091104034232
 Ignore-this: a951a46c93f7f58dd44d93d8623b2aee
] 
[Alter tests to use the new form of set_shareholders
Kevan Carstensen <kevan@isnotajoke.com>**20091104033602
 Ignore-this: 3deac11fc831618d11441317463ef830
] 
[Refactor some behavior into a mixin, and add tests for the behavior described in #778
"Kevan Carstensen" <kevan@isnotajoke.com>**20091030091908
 Ignore-this: a6f9797057ca135579b249af3b2b66ac
] 
[Alter NoNetworkGrid to allow the creation of readonly servers for testing purposes.
Kevan Carstensen <kevan@isnotajoke.com>**20091018013013
 Ignore-this: e12cd7c4ddeb65305c5a7e08df57c754
] 
[Update 'docs/architecture.txt' to reflect readonly share discovery
kevan@isnotajoke.com**20100514003852
 Ignore-this: 7ead71b34df3b1ecfdcfd3cb2882e4f9
] 
[Alter the wording in docs/architecture.txt to more accurately describe the servers_of_happiness behavior.
Kevan Carstensen <kevan@isnotajoke.com>**20100428002455
 Ignore-this: 6eff7fa756858a1c6f73728d989544cc
] 
[Alter wording in 'interfaces.py' to be correct wrt #778
"Kevan Carstensen" <kevan@isnotajoke.com>**20091205034005
 Ignore-this: c9913c700ac14e7a63569458b06980e0
] 
[Update 'docs/configuration.txt' to reflect the servers_of_happiness behavior.
Kevan Carstensen <kevan@isnotajoke.com>**20091205033813
 Ignore-this: 5e1cb171f8239bfb5b565d73c75ac2b8
] 
[Clarify quickstart instructions for installing pywin32
david-sarah@jacaranda.org**20100511180300
 Ignore-this: d4668359673600d2acbc7cd8dd44b93c
] 
[web: add a simple test that you can load directory.xhtml
zooko@zooko.com**20100510063729
 Ignore-this: e49b25fa3c67b3c7a56c8b1ae01bb463
] 
[setup: fix typos in misc/show-tool-versions.py
zooko@zooko.com**20100510063615
 Ignore-this: 2181b1303a0e288e7a9ebd4c4855628
] 
[setup: show code-coverage tool versions in show-tools-versions.py
zooko@zooko.com**20100510062955
 Ignore-this: 4b4c68eb3780b762c8dbbd22b39df7cf
] 
[docs: update README, mv it to README.txt, update setup.py
zooko@zooko.com**20100504094340
 Ignore-this: 40e28ca36c299ea1fd12d3b91e5b421c
] 
[Dependency on Windmill test framework is not needed yet.
david-sarah@jacaranda.org**20100504161043
 Ignore-this: be088712bec650d4ef24766c0026ebc8
] 
[tests: pass z to tar so that BSD tar will know to ungzip
zooko@zooko.com**20100504090628
 Ignore-this: 1339e493f255e8fc0b01b70478f23a09
] 
[setup: update comments and URLs in setup.cfg
zooko@zooko.com**20100504061653
 Ignore-this: f97692807c74bcab56d33100c899f829
] 
[setup: reorder and extend the show-tool-versions script, the better to glean information about our new buildslaves
zooko@zooko.com**20100504045643
 Ignore-this: 836084b56b8d4ee8f1de1f4efb706d36
] 
[CLI: Support for https url in option --node-url
Francois Deppierraz <francois@ctrlaltdel.ch>**20100430185609
 Ignore-this: 1717176b4d27c877e6bc67a944d9bf34
 
 This patch modifies the regular expression used for verifying of '--node-url'
 parameter.  Support for accessing a Tahoe gateway over HTTPS was already
 present, thanks to Python's urllib.
 
] 
[backupdb.did_create_directory: use REPLACE INTO, not INSERT INTO + ignore error
Brian Warner <warner@lothar.com>**20100428050803
 Ignore-this: 1fca7b8f364a21ae413be8767161e32f
 
 This handles the case where we upload a new tahoe directory for a
 previously-processed local directory, possibly creating a new dircap (if the
 metadata had changed). Now we replace the old dirhash->dircap record. The
 previous behavior left the old record in place (with the old dircap and
 timestamps), so we'd never stop creating new directories and never converge
 on a null backup.
] 
["tahoe webopen": add --info flag, to get ?t=info
Brian Warner <warner@lothar.com>**20100424233003
 Ignore-this: 126b0bb6db340fabacb623d295eb45fa
 
 Also fix some trailing whitespace.
] 
[docs: install.html http-equiv refresh to quickstart.html
zooko@zooko.com**20100421165708
 Ignore-this: 52b4b619f9dde5886ae2cd7f1f3b734b
] 
[docs: install.html -> quickstart.html
zooko@zooko.com**20100421155757
 Ignore-this: 6084e203909306bed93efb09d0e6181d
 It is not called "installing" because that implies that it is going to change the configuration of your operating system. It is not called "building" because that implies that you need developer tools like a compiler. Also I added a stern warning against looking at the "InstallDetails" wiki page, which I have renamed to "AdvancedInstall".
] 
[Fix another typo in tahoe_storagespace munin plugin
david-sarah@jacaranda.org**20100416220935
 Ignore-this: ad1f7aa66b554174f91dfb2b7a3ea5f3
] 
[Add dependency on windmill >= 1.3
david-sarah@jacaranda.org**20100416190404
 Ignore-this: 4437a7a464e92d6c9012926b18676211
] 
[licensing: phrase the OpenSSL-exemption in the vocabulary of copyright instead of computer technology, and replicate the exemption from the GPL to the TGPPL
zooko@zooko.com**20100414232521
 Ignore-this: a5494b2f582a295544c6cad3f245e91
] 
[munin-tahoe_storagespace
freestorm77@gmail.com**20100221203626
 Ignore-this: 14d6d6a587afe1f8883152bf2e46b4aa
 
 Plugin configuration rename
 
] 
[setup: add licensing declaration for setuptools (noticed by the FSF compliance folks)
zooko@zooko.com**20100309184415
 Ignore-this: 2dfa7d812d65fec7c72ddbf0de609ccb
] 
[setup: fix error in licensing declaration from Shawn Willden, as noted by the FSF compliance division
zooko@zooko.com**20100309163736
 Ignore-this: c0623d27e469799d86cabf67921a13f8
] 
[CREDITS to Jacob Appelbaum
zooko@zooko.com**20100304015616
 Ignore-this: 70db493abbc23968fcc8db93f386ea54
] 
[desert-island-build-with-proper-versions
jacob@appelbaum.net**20100304013858] 
[docs: a few small edits to try to guide newcomers through the docs
zooko@zooko.com**20100303231902
 Ignore-this: a6aab44f5bf5ad97ea73e6976bc4042d
 These edits were suggested by my watching over Jake Appelbaum's shoulder as he completely ignored/skipped/missed install.html and also as he decided that debian.txt wouldn't help him with basic installation. Then I threw in a few docs edits that have been sitting around in my sandbox asking to be committed for months.
] 
[TAG allmydata-tahoe-1.6.1
david-sarah@jacaranda.org**20100228062314
 Ignore-this: eb5f03ada8ea953ee7780e7fe068539
] 
Patch bundle hash:
4ef2cef7e60bf513a3fc40b2c178dd0363ec6714