We're using cassandra as a key-value store; our values are small. So we're thinking we don't need much disk readahead (e.g., "blockdev -getra /dev/sda"). We're using SSDs.
When cassandra does disk seeks to satisfy read requests does it typically have to read in the entire SStable into memory (assuming the bloom filter said yes)? If cassandra needs to read in lots of blocks anyway or if it needs to read the entire file during compaction then I'd expect we might as well have a big readahead. Perhaps there's a tradeoff between read latency and compaction time. Any feedback welcome. Thanks Donald A. Smith | Senior Software Engineer P: 425.201.3900 x 3866 C: (206) 819-5965 F: (646) 443-2333 [email protected]<mailto:[email protected]> [AudienceScience]
