Elasticache Flashcards
What is Elasticache?
A managed cloud-based web service that provides an in-memory cache.
What benefit does in-memory cache provide?
Provides retrievals from a much faster in-memory cache. reduces reliance on slow disk-based retrievals.
What is caching?
storing of queries for later use. Reduces latency since the application does not repeat queries of the DB, but gets the needed information directly from the cache.
What are the types of Elasticache?
memcached
Redis
What is Memcached?
a widely adopted memory object caching system
Will existing Memcached enabled environments work with AWS Memcached Elasticache service?
yes
What is Redis?
A popular open-source in-memory key-value store that supports data structures such as sorted-sets and lists.
True or false: Elasticache Redis service supports master/slave replication?
True
True or false: Elasticache Redis service supports multi-AZ?
True
True or False: Elasticache Memcached supports multi-AZ?
False. Only Redis supports Multi-AZ
When should you use elasticache?
When your application is read heavy and your DB is overutilized by non-OLAP transactions. OLAP transactions should be offloaded to Redshift.
When should you be careful about using Elasticache?
When your application is write heavy.
Why should you be careful about using Elasticache when your application is write heavy?
When you write to a DB, elasticache will not know about the change until the TTL expires. Users will not get the latest information.
