DocumentDB Flashcards by erik MOLNAR

Overview of DOcDB

fully managed (non-rlational)document DB for MOngoDB workloads
JSON documents(nested key value pairs) stored in collections (~tables)
compatible with majority of mongoDB apps, drives, and tools
high eprformance, scalability, and availability
support for flexible indexing, powerful ad hoc queries and aanlytics
storage and compute can scale independently
supports 15 low latency read replicas (multi-az)
auto scaling of storage from 10GB to 64TB
FAULT TOLERANT AND SELF HEALING STORAGE

AUTOMATIC, CONTINUOUS, incremental backups and PITR

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docdb stores JSON documents (semi structured data)

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key vaue pairs can be nested

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why docdb?

JSON is the defacto format for data exchange
documentDB makes it easy to insert, query, index, and perform aggregations over JSON data
store JSON output from APIs straight into DB and start analyzing it
flexible document model, data types, and indexing
add/remove indexes easily

run ad hoc queries for operational and analytics workloads

for known access patterns - use dynamoDB instead

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DocDB architecture

___ copies of your data across ___ AZs

6, 3

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DocDB Architecture

_____ optimistic algorithm (quorum model)

lock-free

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docdb architecture

___ copies out of 6 needed for writes (__/6 write quorum - data considered durable whe at least __/6 copies acknowledge the write)

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docdb architecture

___ copies out of 6 needed for reads (__/6 read quorum

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docdb architecture

self healing with ____ replication, storage is striped across 100s of volumes

peer to peer

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docdb architecture

___ docdb isntance takes writes(master)

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___ nodes on replicas do not need to write/replicate (=improved read performance)

compute

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docdb architecture

log-structured distributed storage layer - passes ___ log records from compute to stroage layer (=faster)

incremental

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docdb architecture

master + up to ___ read replicas server reads

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docdb architecture

data is continuously backed up to __ in real time, using storage nodes (compute nore perfomance is unaffected)

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docdb cluster

recommended to connect using the cluster endpoint in replica set mode (enables your SDK to auto discover the cluster arrangement as instances get added or removed from the cluster)

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docdb replication

up to ___ read replicas

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docdb replication

____ repliaction

ASYNC

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docdb replication

replicas share the same underlying storage layer

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docdb replication

typically take 10s of milliseconds (replication lag)

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docdb replication

minimal performance impact on the primary due to replication process

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docdb HA failovers

-failovers occur automatically

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docdb HA failovers

-a replica is automatically promoted to be the new primary during DR

docdb HA failovers

docdb flops the CNAME of the DB instance to point ot the replica and promotes it

docdb HA failovers

failover to a replica typically takes 30 seconds ( minimal downtime)

docdb HA failovers creating a new instance takes about 8-10 minutes (post failover)

docdb backup and restore - supports automatic backups

docdb backupa dn restore continuously backs up your data to s3 for PITR (max retention period of \_\_days)

docdb backup and restore latest restorable time for a PITR can be up to 5 minutes in the past

docdb backup and restore - the first backup is a full backup - subsequent backups are \_\_\_\_

incremental

docdb backup and restore take manual snapshots to retain beyond 35 days

docdb backup and restore backup process dfoesnot impact cluster performance

docdb backup and restore - can only restore to a new cluster

docdb backup and restore can restore an unencrypted snapshot to an encrypted cluster (but not hte other way round)

docdb backup and restore to restore a cluster from an encrypted snapshot, you must have access to the KMS key

docdb backup and restore can only share manual snapshots (can copy and share auto ones)

docdb backup and restore can't share a snaptho encrypted using the defaut KMS keys of teh a/c

docdb backup and restore shapshots can be shared across accounts, but within the same region

docdb scaling - mongoDB sharding not supported (instead offers read replicas/vertical scaling/storage scaling) - vertical scaling (scale up/down - by resizing instances - horizontal scaling (scale out/in) by adding /removing up to 15 replicas - can scale up a replica independently from other replicas (typically for analytical workloads

docdb security - IAM and Network - you use IAM to manage docdb resources

docdb security - IAM and Network supports mongodb default auth ____ for db authentication

SCRAM(Salted Challenge Respose Authentication Mechanism)

docdb security - IAM and Network supports built in roles for DB users with \_\_\_\_

RBAC(role based access control)

docdb security - IAM and Network docdb clusters are VPC only (use private subnets)

docdb security - IAM and Network clients (mongodb shell) can run on ec2 in public subnets wihtin VPC

docdb security - IAM and Network can connect to your on prem IT infra via VPN

Docdb security - encryption encryption at rest - AES-256 using KMS -applied to cluster data/replicas/indexes/logs/backups/snapshots encryption in transit - using TLS -to enable TLS, set tls parameter in cluster param group to conenct over TLS: download the cert (public key) from AWS -pass the cert key while connecting to the cluter

docdb pricing - on demand instances - pricing per second with a 10 min minimum - IOPS - per million IO requests - each DB page reads operation from teh storage volume counts as one IO (one page = 8KB) - write IOs are counted in 4KB units DB storage - per GB per month backups - per GB per month(backups up to 100% of your clusters data storage is free) data tarnsfer - per GB can temporarily stop compute instances for up to 7 days

docdb monitoring API calls logged with \_\_\_\_

cloudtrail

docdb monitoring common CW metrics - CPU or RAM utilization - CPUUtilization/FreeableMemory - IOPS metrics - VolumeReadIOPS/VulumeWriteIOPS/WriteIOPS/ReadIOPS - Databaes conenctions - DatabaseConnections - Network Traffic - NetworkThroughput - Storage volume consumption - VolumeBytesUsed

docdb monitoring -two types of logs can be published/exported to CW logs profiler logs audit logs

docdb profiler - logs (into CW logs) the details of ops performed on your cluster - helps identify slow operations and improve quey performance - accesible from CW logs - to anable: - set parameters, profiler, profiler\_threshold\_ms, and profiler\_sampling\_rate - enable logs exports for audit logs by modifying the intance - both the steps above are mandatory

docdb audit logs - records DDL statements, authentication, authorization, and user mgmt events to CW logs - exports your cluster's auditing records (JSON docs) to CW logs - accessible from CW logs to enable: - set parameter audit\_logs=enabled - enable logs exports for audit logs by modifying the instance

docdb performance management - use explain command to identify slow queries db. runComamnd({explain: {}}) - can use db.adminCommand to find and terminate queries example: to terminate long running /blocked queries db. adminCommand({killOp: 1, op: });