ISSUE SUMMARY
If a secondary node is shut down during phase 2 of an index build (constructing the B-Tree), it will not attempt to rebuild the index upon restart and leave behind a corrupted index catalog. Subsequent inserts on the primary that are replicated to this secondary node will crash the secondary node.
USER IMPACT
A secondary node affected in this way has to be resynced or repaired. This only happens during abnormal termination of the mongod process with an index build in progress. Normal shutdown will not trigger this issue.
SOLUTION
On startup, incomplete index builds need to be cleaned up. The index creation needs to be manually restarted.
WORKAROUNDS
None.
AFFECTED VERSIONS
All versions from 2.4.0 to 2.4.9 are affected by this bug. The 2.6 series is unaffected by the issue.
PATCHES
The fix is included in the 2.4.10 production release.