Hi folks, A question like this was recently asked, but I don't think anyone ever supplied an unambiguous answer. We have a set of clusters currently using sequential repair, and we'd like to transition them to incremental repair. According to the documentation, this is a very manual (and likely time-consuming) process:
http://docs.datastax.com/en/cassandra/2.1/cassandra/operations/opsRepairNodesMigration.html Our understanding is that this process is necessary for tables that use LCS, as unrepaired tables are compacted using STCS and (without the process described in the doc) all tables start in the unrepaired state. The pain of this migration strategy is supposed to be offset by the savings in undesired compaction activity. The docs aren't especially clear, but it sounds like this strategy is not needed for tables that use STCS. However, CASSANDRA-8004 (resolved against 2.1.2) appears intended to have both the repaired and unrepaired sstable sets use the same compaction strategy. It seems like that obviates the rationale for a migration procedure, which is supported by offhand comments on this list, e.g.: https://www.mail-archive.com/user%40cassandra.apache.org/msg40303.html https://www.mail-archive.com/user%40cassandra.apache.org/msg44896.html In other words, it *looks* like the docs are obsolete, and the migration process for existing clusters only consists of flipping the switch (i.e., adding "-inc" to invocations of "nodetool repair"). Our questions: 1) Is our understanding of the status quo following 2.1.2 correct? Does migrating existing clusters to incremental repair only require adding the "-inc" argument, or is a process still required? 2) If a process is still required, have there been any changes since 2.1.2? Are the docs up-to-date? 3) If there is no process or if the process has changed, are there plans on the DataStax side to update the documentation accordingly? Thanks, SK
