→ System Design → Start Learning / Download MP3 Flashcards

Question		Answer
what Cassandra is start learning		wide-column store
Couchdb start learning		alternative to MongoDb. An open-source document-oriented NoSQL database, implemented in Erlang
four examples of Wide-column store start learning		Apache Cassandra, Apache HBase, BigTable, scylla
Database replication master/slave start learning		Master -original, only writes, slaves - copies, only reads
expand CDN start learning		Content Delivery Network
expand SPOF start learning		Single point of failure
Cache eviction policies start learning		LRU - Least recently used, LFU - Least Frequently used, FIFO - First in First out
CDN - describe what it is start learning		A CDN is a network of geographically dispersed servers used to deliver static content. CDN servers cache static content like images, videos, CSS, JavaScript files, etc.
Data Lake start learning		is a system or repository of data stored in its natural/raw format,[1] usually object blobs or files
Stateless Web Tier start learning		session is kept in NoSQL database. It is no longer kept in web server. Each server in the cluster can access state data from the database
Load balancer, sticky session start learning		user who authenticated in one of the servers in a cluster, will be redirected to the same server for future calls (for certain amount of time that is longer than the session timeout)
Disadvantages of sticky session start learning		more difficult to add or remove servers, more difficult to handle server failures
Advantages of stateless web tier vs stateful web tier start learning		simpler, more robust and scalable
Shared data store for state data (sessions), what to use start learning		memcached/Redis, NoSQL
geoDNS start learning		geolocation DNS routing - to make sure, that the client is directed to the closest datacenter
Logging and monitoring tool start learning		Datadog, Matomo, prometeus, Pendo
example of Key business metrics start learning		daily active users etc
Shard start learning		each shard has the same schema, but data are specific to shard- user data is allocated to specific shard - hash function is used to find the shard e.g. user_id % 4
Sharding key vs partition key start learning		Sharding key vs partition key
Two Problems with sharding start learning		Resharding data - r.g. One shard goes down, Celebrity problem = hotspot key problem
Nanosecond start learning		10^-9
Microsecond start learning		10^-6
Millisecond start learning		10^-3
2^10 start learning		1KB ~ 1 000
2^20 start learning		1MB ~ 1 000 000
2^30 start learning		1GB ~ 1 000 000 000
2^50 start learning		1PB ~ 1 000 000 000 000 000
L1 cache start learning		A memory bank built into the CPU chip. Also known as the "primary cache," an L1 cache is the fastest memory in the computer and closest to the processor.
Fan-out service start learning		is a messaging pattern used to model an information exchange that implies the delivery (or spreading) of a message to one or multiple destinations possibly in parallel
Amazon sns start learning		simple notification service
Amazon EC2 - expand start learning		Amazon Elastic Compute Cloud
Amazon EC2 - describe start learning		allows users to rent virtual computers on which to run their own computer applications
Amazon EBS - expand start learning		Amazon Elastic Block Store
Amazon EBS - expand start learning		block level storage volumes for use with EC2 instances. You can create a file system on top of these volumes, or use them in any way you would use a block device (such as a hard drive)
Amazon DynamoDB start learning		is a fully managed proprietary NoSQL database service that supports key–value and document data structures
Amazon Aurora start learning		is a relational database service developed and offered by Amazon Web Services beginning in October 2014 Aurora is available as part of the Amazon Relational Database Service (RDS).
Amazon sqs start learning		simple queue service
memcached start learning		Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.
2^40 start learning		1 000 000 000 000 = 1TB
L1 cache reference start learning		0.5 ns
L2 cache reference start learning		7 ns
Mutex lock/unlock start learning		100 ns
Main memory reference start learning		100 ns
Compress 1KB with zippy start learning		10 microseconds = 10000 ns
Send 1KB via 1Gbps network start learning		10 microseconds
read 1MB sequentially from memory start learning		250 microseconds
read 1MB sequentially from disk start learning		30 ms
read 1MB sequentially from network start learning		10 ms
sharding vs partitioning start learning		The difference is that sharding implies the data is spread across multiple computers while partitioning does not. Partitioning is about grouping subsets of data within a single database instance
consistent hashing start learning		consistent hashingConsistent hashing is a special kind of hashing such that when a hash table is re-sized and consistent hashing is used, only k/n keys need to be remapped on average, where k is the number of keys, and n is the number of slots
consistent hashing describe algorithm start learning		To determine which server a key is stored on, we go clockwise from the key position on the ring until a server is found.

System design

You must sign in to write a comment

More