DDIA, chapter 8, The Trouble With Distributed Systems

What fits better to word Deterministic?

• some parts of the system that are broken in some unpredictable way

• well defined (algorithm)

• the same operation always produces the same result

• monotonic(clock)

A network problem can occur:

• while using a public cloud service

• in controlled environments like a datacenter operated by one company

• between two service connected through Internet

How long should be the timeout to surely detect a faulting node?

• short timeout to detect problem faster

• long timeout to lower a risk of incorrectly declaring a node dead

• there is no simple answer

What kind of network uses bounded delay?

• cellular

• VoIP

• traditional fixed-line telephone network

Which type of clock is more reliable for LWW (last write wins) strategy?

• logical clock

• monotonic clock

• time-of-day clock

Select features of RTOS (Real time operating system):

• High performance

• very expensive

• guaranteed allocation of CPU time in specified intervals

• dynamic memory allocation may be restricted or disallowed entirely

What is fencing token?

• a lock granted by server

• a number that increases every time a lock is granted by server

• a check on a client side to ensure that lease is not expired

• timestamp range used to calculate the order of operations

bounded network delay, bounded process pauses, and bounded clock error are attributes of:

• Synchronous model

• Partially synchronous model

• Asynchronous model

if we are generating fencing tokens for a lock, we may require the algorithm to have the following properties:

• availability

• eventual consistency

• monotonic sequence

• uniqueness