High Availability Flashcards
EC2
_____ - increases intance sizes as required, using reserved instances
___ - increase teh number of ec2 instances, based on autoscaling
scalability
elasticity
DynamoDB
___-unlimited amount of storage
___ = increase additional IOPS for additional spikes in traffic. Decrease that IOPS after teh spike.
scalability
elasticity
RDS
____ - increase instance size, ie: from small to medium
___ = not very elastic, can’t scale RDS based on demand
scalability
elasticity
_____ RDS allows:
scalability - modify the instance type
elasticity - ____ serverless
aurora
____ allows you to have an exact copy of your prod database in anotehr AZ. aws handles the replication for you, so when your prod DB is written to, this write will automatically be synchronized to the stand by DB. in the event of planned DB maintenance, DB instance failure, or an AZ failure, RDS will automatically failover to the standby so that DB operations can resume quickly without administrative intervention.
Multi-AZ
multi-az deployments for the mysql, oracle, postgresql engines utilize___ physical repl;ication to keep data on teh standby up to date with teh primary
multi-az deloyment for the sql server engines use ____ logical replication to scheive the same result, employing SQL server native mirroring technology.
Both approaches safeguard your data in teh event of a DB instance failure or loss of a AZ
synchronous
RDS multiAZ failover advantages
- high availability
- backups are taken from ____ whih avoids IO suspension to the primary
- restores are taken from ____ which avoids IO suspension to teh primary
secondary
T or F
you can force failover from one AZ to anotherby rebooting your instance. This can be done through the AWS management console or by using RebootDBInstance API call.
T
RDS multi AZ is a scaling solution
T or F
False
It is not a scaling solution
T or F
AMazon handles the failover for you. Done by updating the private DNS for the DB endpoint.
T
Bcakups and Restores are taken from the secondary multi-az instance.
T or F
T
T or F
read replcas are used to scale
T
RDS ___ ____ make it easy to take advantage of supported engiens built in replication functionality to elastically scale out beyond the capacity constraints of a single DB instance for read heavy DB workloads.
read replicas
T or F
you can create a read replica with a few clicks in teh aws mgmt console or using the CreateDBINtanceREadReplica API. once the read replica is created, DB upadtes on the source DB instance will be replicated using a supported engine’s native, asynchronous replication. You cna create multiple read replicas for a given source DB instance and distribute your app’s read traffic amongst them.
T
when to use read replicas -
scaling beyond the compute or IO capacity of a single DB instance for read heavy DB workloads. This excess read traffic can be directed to one or more REAd replicas.
serving read traffic while the source DB instance is available. if your source DB instance cannot take IO requests (due to IO suspension for backups or scheduled maintenance), you can direct read traffic to your read replicas.
Business reporting or data warehousing scenarios; you may want business reporting queries to run against a read replica, rather than your primary prod DB instance.
t
Read replica supported verisons:
myqsl
postgresql
mariaDB
for all 3, amazon uses these engines native ____ rerpliction to update the read replica
asyncronous
aurora read replicas
employs an ___ backed virtualized storage layer purpose built for DB workloads. aurora replica share the same underlying storage as teh source instance, lowering costs and avoiding the need to copy data to the replica nodes.
SSD