Concepts Flashcards
What are the 3 types of data store persistence?
Persistent
Transient
Ephemeral
What is persistent data store?
Durable, persists after reboots, restarts, power cycles, etc. Think S3, Glacier, RDS.
What is transient data store?
temporarily stored data until passed to another process of data store. Think SQS, SNS
What is ephemeral data store?
Data that is lost once the process ends. Think EC2 Instance Store, Memcached
What is the difference between IOPS and throughput?
IOPS is a measure of read and write speed
Throughput is a measure of how much data can be moved at a time.
What are the two consistency models?
ACID and BASE
What does ACID stand for in the ACID consistency model?
Atomic
Consistent
Isolated
Durable
What does Atomic mean in the ACID consistency model?
Transactions are all or nothing (no partial stores)
What does Consistence mean in the ACID consistency model?
Transactions must be valid
What does isolated mean in the ACID consistency model?
Transactions can’t interfere with one another (one transaction can’t effect another)
What does Durable mean in the ACID consistency model?
Completed transactions must stick around
What does BASE stand for in the BASE consistency model?
Basic Availability
Soft-state
Eventual Consistency
What does Basic Availability mean in the BASE consistency model?
values availability even if the data is stale
What does soft-state mean in the BASE consistency model?
Might not be instantly consistent accross data stores
What does Eventual Consistency mean in the BASE consistency model?
Will achieve consistency at some point
