Tuning NodeSync validations
Configure NodeSync validation rate to meet target deadlines.
system.log
The location of the system.log file is:- /var/log/cassandra/system.log
NodeSync tries to validate all tables within their respective deadlines, while respecting the
configured rate limit. If a table is 10GB and has a
deadline_target_sec=10 and
the rate_in_kb is set to 1MB/sec, validation will
not happen quickly enough. Configure the rate and deadlines realistically, take data sizes
into account and adapt with data growth.Important: For write-heavy workloads, where more than 20% of the operations are writes,
you may notice CPU consumption overhead associated with NodeSync. If that's the case for you
environment, DataStax recommends using
nodetool repair instead of enabling
NodeSync. See nodetool repair.NodeSync records warnings to the system.log, if it detects any
of the following conditions:
- rate_in_kb is too low to validate all tables within their deadline, even under ideal circumstances.
- rate_in_kb cannot be sustained by the node (too high for the node load/hardware).