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https://issues.apache.org/jira/browse/ACCUMULO-1771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13815071#comment-13815071
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Keith Turner commented on ACCUMULO-1771:
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bq. Is this a dupe or abstraction of ACCUMULO-1766?
Its not a dupe of ACCUMULO-1766, but its caused by different code making the
same assumption. The code treats the first configured URI specially. I am
thinking the list of uris should be used as list of possible places to store
new files. The configured list of uris does not represent all of the
locations that Accumulo has stored files in the past.
# User initializes with URI_1 in config, runs w/ this for a bit, then changes
config to contain URI_2 and URI_3.
# User initializes with URI_1 and URI_2, runs w/ this for a bit, then changes
config to URI_0, URI_1, and URI_2
# User initializes with URI_1 and URI_2, user wants to reinit so they clear
URI_1 (but forget to clear URI_2), User initializes again with URI_1 and URI_2
# User initializes instance 1 with URI_1. User initializes instance 2 with
URI_2. User shuts down both instances and adds URI_2 to instance 1 config.
In scenario 1 Accumulo will probablly not start because because it will look
for the instance id and data version at URI_2. In secnario 2 Accumulo will
look for instance id and data version at URI_0. In scenario 3 initialization
may succeed even though URI_2 is dirty. Scenario 4 shows adding a dirty URI to
an existing instance.
A possible solution is the following.
* init checks and initializes all URIs configured at the time it runs (upgrade
would also need to do this)
* master, tserver, etc check the set of URIs when they start and ensure
instance id and data version are consistent across all. If server processes
ever reload this prop, the check would need to be redone.
* provide a utility to initialize a new URI. This utility would fail if the
URI is not clean. The utility would have to be run before adding the URI to
the Accumulo config.
Another possible solution is to store the list of URIs in zookeeper and provide
instance operations for mutating that list.
> Instance id and version info only stored on one hdfs instance
> -------------------------------------------------------------
>
> Key: ACCUMULO-1771
> URL: https://issues.apache.org/jira/browse/ACCUMULO-1771
> Project: Accumulo
> Issue Type: Sub-task
> Components: master, tserver
> Reporter: Keith Turner
> Priority: Critical
> Fix For: 1.6.0
>
>
> When instance.volumes contains multiple uris only the first one is
> initialized with the data version and instance id. If the user changes the
> order of the uris in the config, it seems like Accumulo will stop working
> correctly.
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