From 1fcaa5d37ce24b36a731fd75053e167f18026762 Mon Sep 17 00:00:00 2001
From: Daira Hopwood <daira@jacaranda.org>
Date: Thu, 5 Sep 2013 19:16:27 +0100
Subject: [PATCH] Mon Jul 2 00:08:43 BST 2012 david-sarah@jacaranda.org *
[1.9.2 branch] Add comments and a caveat in webapi.rst indicating that the
needs-rebalancing field may be computed incorrectly. refs #1115 refs #1784
---
docs/frontends/webapi.rst | 14 +++++++++-----
src/allmydata/immutable/checker.py | 1 +
src/allmydata/immutable/filenode.py | 2 ++
3 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/docs/frontends/webapi.rst b/docs/frontends/webapi.rst
index c4d7dd01..853a6f76 100644
--- a/docs/frontends/webapi.rst
+++ b/docs/frontends/webapi.rst
@@ -1347,7 +1347,9 @@ mainly intended for developers.
count-shares-needed: 'k', the number of shares required for recovery
count-shares-expected: 'N', the number of total shares generated
count-good-share-hosts: the number of distinct storage servers with good
- shares
+ shares. Note that a high value does not necessarily
+ imply good share distribution, because some of
+ these servers may only hold duplicate shares.
count-wrong-shares: for mutable files, the number of shares for
versions other than the 'best' one (highest
sequence number, highest roothash). These are
@@ -1362,10 +1364,12 @@ mainly intended for developers.
list-corrupt-shares: a list of "share locators", one for each share
that was found to be corrupt. Each share locator
is a list of (serverid, storage_index, sharenum).
- needs-rebalancing: (bool) True if there are multiple shares on a single
- storage server, indicating a reduction in reliability
- that could be resolved by moving shares to new
- servers.
+ needs-rebalancing: (bool) This field is intended to be True iff
+ reliability could be improved for this file by
+ rebalancing, i.e. by moving some shares to other
+ servers. It is not guaranteed to be computed correctly
+ in Tahoe-LAFS up to and including v1.9.2, and its
+ precise definition may change in future versions.
servers-responding: list of base32-encoded storage server identifiers,
one for each server which responded to the share
query.
diff --git a/src/allmydata/immutable/checker.py b/src/allmydata/immutable/checker.py
index 4b7a0059..8561ab45 100644
--- a/src/allmydata/immutable/checker.py
+++ b/src/allmydata/immutable/checker.py
@@ -796,6 +796,7 @@ class Checker(log.PrefixingLogMixin):
# The file needs rebalancing if the set of servers that have at least
# one share is less than the number of uniquely-numbered shares
# available.
+ # TODO: this may be wrong, see ticket #1115 comment:27 and ticket #1784.
cr.set_needs_rebalancing(d['count-good-share-hosts'] < d['count-shares-good'])
cr.set_data(d)
diff --git a/src/allmydata/immutable/filenode.py b/src/allmydata/immutable/filenode.py
index c7fa82f6..6d961e99 100644
--- a/src/allmydata/immutable/filenode.py
+++ b/src/allmydata/immutable/filenode.py
@@ -131,6 +131,8 @@ class CiphertextFileNode:
prr.set_healthy(is_healthy)
prr.set_recoverable(is_recoverable)
crr.repair_successful = is_healthy
+
+ # TODO: this may be wrong, see ticket #1115 comment:27 and ticket #1784.
prr.set_needs_rebalancing(len(sm) >= verifycap.total_shares)
crr.post_repair_results = prr
--
2.45.2