AWS DynamoDB Accelerator (DAX) 101

Introduction to AWS DynamoDB Accelerator (DAX)

1. DAX 101 1 2020/2/15 Kenju Wagatsuma
2. DAX Wrap Up 2
3. DAX is… DynamoDB-specific in-memory cache store 3
4. [DAX] Glossary of Terms 4 5FSN %FTDSJQUJPO /PEFT "
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6. [DAX] Single-leader Replication 6 +3 nodes for different Multi-A/Z for production Background replication (eventually consistent model) Single “primary node” handles all write requests
7. Subnet C Subnet B DAX Cluster Subnet A [DAX] Single-leader Replication - Write 7 Primary Replica Replica
8. DAX Cluster [DAX] Single-leader Replication - Write 8 Primary Replica Replica Application DynamoDB Table DynamoDB Table Write Read
9. DAX Cluster [DAX] Single-leader Replication - Replicate 9 Primary Replica Replica Application DynamoDB Table DynamoDB Table Write Read
10. DAX Cluster [DAX] Single-leader Replication - Read 10 Primary Replica Replica Application DynamoDB Table DynamoDB Table Write Read
11. [DAX] Cache Algorithm 11 Least Recently Used (LRU) cache Negative cache also implemented Eviction happens when items are taken & cache is full Global Time-To-Live (TTL)
12. [DAX] Item Cache / Query Cache 12 Item Cache Query Cache Operation GetItem / BatchGetItem Query / Scan Metrics ItemCacheHits/ItemCacheMisses QueryCacheHits/QueryCacheMisses ScanCacheHits/ScanCacheMisses
13. [DAX] Write Strategy - Write-Through 13 #write #read Application DAX DynamoDB Application DAX DynamoDB
14. [DAX] Write Strategy - Write-Around 14 #write #read Application DynamoDB Application DAX DynamoDB
15. [DAX] Write Strategy 15 8SJUF
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16. [DAX] Within VPC + Multi-A/Z 16
17. [DAX] Limitation 17 Maximum nodes is 10 (1 primary node + ~9 replica nodes) Maximum nodes is 50 per Region. Maximum Parameter Groups is 20 per Region Maximum DAX Subnet Groups is 50 per Region. Maximum subnets per groups is 20.
18. Monitoring 18
19. [Monitoring] CloudWatch Metrics 19 NFUSJDT EFTDSJQUJPO $166UJMJ[BUJPO 
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20. [Monitoring] CloudWatch Metrics 20 NFUSJDT EFTDSJQUJPO 5ISPUUMJOH3FRVFTU$PVOU 
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22. [Monitoring] Grafana 22
23. [Monitoring] SLI/SLO 23
24. Alerting 24
25. [Alerting] CW Alarm - Infrastructure 25 CW Alarm SNS Topic Lambda Slack
26. [Alerting] CW Alarm - CPUUtilization 26
27. [Alerting] CW Alarm - Cache Hit Ratio 27 ItemCacheHitRatio = ItemCacheHits / ( ItemCacheHits + ItemCacheMisses )
28. [Alerting] CW Alarm - Cache Hit Ratio 28
29. [Alerting] DAX Events - Infrastructure 29 DAX Event SNS Topic Lambda Slack
30. [Alerting] DAX Events - Infrastructure 30 failure/success in adding a node changes to the security groups