concepts

Question 0

CAP theorem

Answer 0

Consistency
Availability
Partition tolerance

Only two can be guaranteed

Question 1

ACID property

Answer 1

Atomicity
Consistency
Isolation
Durability

Question 3

File system distribute/replicate

Answer 3

• Replicate at block level or file level
• Gluster FS is an e.g. of a distributed FS
• File can change master if user travelled
• collaboration like version control systems
• gluster for e.g. gives option to either be consistent OR partition tolerant (in latter case there is merge when connectivity restores)
• Another nice medium ground is three replica setup where if 2 partitions can still talk their data takes precendence over single node’s data (if conflict)

Question 4

What is data striping?

Answer 4

When processing device requires data faster from storage, spread segments of storage to different physical devices and parallelize reads.

Question 5

Throughput and latency connected?

Answer 5

Pipe analogy. Width of pipe defines throughput, length defines latency. Throughput limits indirectly affect latency because of addition of ‘queueing delay’ (Entry into the pipe)

Question 6

Disaggregated compute

Answer 6

Split apart storage and compute layers to scale them separately. Reduces wasted resources of one over the other if tightly bound.

Question 7

Erasure coded pools?

Answer 7

Data storage technique in distributed environments. Replicate chunks with a factor to be resilient to failures.. HDFS like.

Question 8

BASE properties of system?

Answer 8

For NoSQL based systems – Basically available, soft state, eventual consistent

Question 9

Shared nothing arch?

Answer 9

In a way to scale most, no bottlenecks on shared resources.