[jira] [Created] (CASSANDRA-6156) Poor resilience and recovery for bootstrapping node - "unable to fetch range"

["Alyssa Kwan (JIRA)" <ji...@apache.org>]

Alyssa Kwan created CASSANDRA-6156:
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             Summary: Poor resilience and recovery for bootstrapping node - "unable to fetch range"
                 Key: CASSANDRA-6156
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6156
             Project: Cassandra
          Issue Type: Bug
          Components: Core
            Reporter: Alyssa Kwan
             Fix For: 1.2.8


We have an 8 node cluster on 1.2.8 using vnodes.  One of our nodes failed and we are having lots of trouble bootstrapping it back.  On each attempt, bootstrapping eventually fails with a RuntimeException "Unable to fetch range".  As far as we can tell, long GC pauses on the sender side cause heartbeat drops or delays, which leads the gossip controller to convict the connection and mark the sender dead.  We've done significant GC tuning to minimize the duration of pauses and raised phi_convict to its max.  It merely lets the bootstrap process take longer to fail.

The inability to reliably add nodes significantly affects our ability to scale.

We're not the only ones:  http://stackoverflow.com/questions/19199349/cassandra-bootstrap-fails-with-unable-to-fetch-range

What can we do in the immediate term to bring this node in?  And what's the long term solution?

One possible solution would be to allow bootstrapping to be an incremental process with individual transfers of vnode ownership instead of attempting to transfer the whole set of vnodes transactionally.  (I assume that's what's happening now.)  I don't know what would have to change on the gossip and token-aware client side to support this.

Another solution would be to partition sstable files by vnode and allow transfer of those files directly with some sort of checkpointing of and incremental transfer of writes after the sstable is transferred.



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