CassandraAdmin Flashcards
Purpose of seed nodes? (2)
- Bootstrapping (adding new node) 2. In case gossip loses its mind
What is the leveled compaction multiplier?
10x per level
What type of workload is best for leveled comparison?
read-heavy
Which compaction strategy saves the most disk space?
leveled compaction
The biggest problem with leveled compaction?
I/O intensity
Can you create a keyspace by specifying a non-existent multi-dc keyspace?
Yes.
What does sstabledump do?
Dump contents of a given SSTable to standard output in JSON format. Good for diagnostics. Includes tombstones.
What are the 4 states for each node?
joining, leaving, up, and down
By default now many vnodes does each node have?
128 per Cassandra quiz. In my experience, it has been 256.
cassandra.yaml parameter that configures vnodes?
num_tokens
What does snitch do?
determines each node’s rack and data center
3 types of snitch?
SimpleSnitch, PropertFileSnitch, DynamicSnitch
With RF=2, how many nodes must respond with success using consistency level quorum to indicate a successful operation?
2
What is the default time for a node to store a hint?
3 hours
Is hinted handoff enabled or disabled by default?
Enabled.
Read repair ALWAYS occurs in which consistency level?
ALL
SStable stands for…
Sorted Stream Table
What does the partition summary store?
Byte offsets into the partition index
Which structures are stored on disk?
SStable and partition index (also commit log).
What is the partition index?
The structure on disk that contains bytes offsets for sstables.
What is the index of the partition index?
The partition summary, stored in ram to limit search in partition index. summary->index->sstable
Structures stored in ram?
key cache, partition summary, bloom filter (bloom filter is off heap)
What does CPU wait mean?
Roughly the amount of time a task has to wait on CPU resources.
What does dstat show?
CPU, disk I/O, network for all processes
