blambov commented on code in PR #2712: URL: https://github.com/apache/cassandra/pull/2712#discussion_r1371527733
########## doc/modules/cassandra/pages/managing/operating/compression.adoc: ########## @@ -145,6 +140,17 @@ immediately, the operator can trigger an SSTable rewrite using `nodetool scrub` or `nodetool upgradesstables -a`, both of which will rebuild the SSTables on disk, re-compressing the data in the process. +== Other options + +* `crc_check_chance` (default: `1.0`): determines how likely Cassandra +is to verify the checksum on each compression chunk during reads to +protect against data corruption. Unless you have profiles indicating +this is a performance problem it is highly encouraged not to turn this +off as it is Cassandra's only protection against bitrot. This option was part Review Comment: How about "In earlier versions of Cassandra a duplicate of this option existed in the compression configuration. The latter was deprecated in Cassandra 3.0 and removed in Cassandra 5.0."? ########## doc/modules/cassandra/pages/developing/cql/cql_singlefile.adoc: ########## @@ -579,6 +579,14 @@ link:#compressionOptions[below]. |`caching` |_map_ |_see below_ |Caching options, see link:#cachingOptions[below]. + +|`crc_check_chance` |simple|1.0|When compression is enabled, each compressed Review Comment: This looks a bit incorrect. We do generate checksums for all data files, but we only check them on reads with compressed files (in part because it's impossible to do for the memory-mapped access mode). Perhaps "This option defines the probability with which checksums should be checked during reads to detect bit rot and prevent the propagation of corruption to other replicas. The default value is 1 to apply a checksum every time a data chunk is read. Set to 0 to disable checksum checking and to 0.5 for instance to check every other read. Due to technical limitations we only currently apply this for compressed files. If compression is not enabled on the table, no checksums will be verified."? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
