Aishwarya Ganesan created CASSANDRA-12682:
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Summary: Silent data corruption and corruption propagation in
Cassandra
Key: CASSANDRA-12682
URL: https://issues.apache.org/jira/browse/CASSANDRA-12682
Project: Cassandra
Issue Type: Bug
Reporter: Aishwarya Ganesan
Corruptions in Cassandra's SSTable data can be silently returned to users if
SSTable compression is disabled.
Cassandra maintains a digest.crc32 and CRC.db in the sstable directory but
fails to detect the corruptions to SSTable Data.db. Without this, Cassandra is
vulnerable to silent corruptions resulting from underlying problems in disks
and file systems atop them. Research support the need for end to end integrity:
https://research.cs.wisc.edu/wind/Publications/zfs-corruption-fast10.pdf
http://www.cs.toronto.edu/~bianca/papers/fast08.pdf
In a small test case where the underlying disk/FS corrupts a particular block
holding the user data, Cassandra can silently return corrupted user data on a
read request. Also, the read repair or anti-entropy can propagate the corrupted
data to other intact replicas when the corrupted value is lexically greater.
This is because a corruption doesn't change the timestamps and timestamp
conflicts are resolved by choosing the data with the highest value. (We
reproduced this scenario using our testing framework)
Why does Cassandra not use the CRC and digests to verify the integrity of data
in the SStables on read? Are the digest.crc32 and CRC.db files ever used?
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