Video and slides synchronized, mp3 and slide download available at URL https://bit.ly/2Cnu9Td. Alan Kasindorf explores the possibility of using new storage devices to reduce DRAM dependency for cache workloads and talks about use cases that optimize for different cache workloads. Filmed at qconsf.com. Alan (Dormando) Kasindorf is OSS Memcached Project Maintainer. Previously, he was Memcache / Mcrouter at Facebook and Director of Edge Engineering at Fastly.

1. CACHING BEYOND RAMCACHING BEYOND RAM
memcached.org/blog
@dormando

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Watch the video with slide
synchronization on InfoQ.com!
https://www.infoq.com/presentations/
nvme-cache

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4. WHY RAM?WHY RAM?

5. W W W
Identical Cache

6. W W W
Broadcast Invalidation

7. MC
MC
HASH(key)

8. W DB
1G RAM 4G RAM
32bit OS!

9. W DB
4G RAM 4G RAM
Filled Empty
RAM Slots

10. W
DB
16G RAM
4G RAM
W
W W

11. ENTER FLASHENTER FLASH

12. FLASH! NOT JUST FOR HEAVYFLASH! NOT JUST FOR HEAVY
MACHINERYMACHINERY

13. X25-M 80G IOPS: 35k read, 300 write
X25-E 64G IOPS: 35k read, 3300 write

14. V
LB
RAM cache!
Sticky L7
V
V
V

16. LB
Flash Cache!
Sticky L7
V
V X25-E
X25-E

17. BAM!BAM! CDNCDN

18. GOOD (ENOUGH) SSD'S AREGOOD (ENOUGH) SSD'S ARE
EVERYWHEREEVERYWHERE

19. TRADEOFFSTRADEOFFS

20. Moneta [SET]
REND MC
STORE

21. Moneta [MISS]
REND MC
STORE

22. Moneta [MISS]
REND MC
STORE

23. Moneta [MISS]
REND MC
STORE

24. CACHE -> DB -> DBCACHE -> DB -> DB

25. ARE SMALL ITEMS VALUABLE ON DISKARE SMALL ITEMS VALUABLE ON DISK
CACHE?CACHE?

26. NO.NO.

27. MEMCACHED EXTSTOREMEMCACHED EXTSTORE

28. RAM DISK
* metadata
* key
* pointer
* metadata
* key
* value

29. RAM
HEAD
TAIL
Write Buffer
DISK

30. Bad: Still limited by RAM.
Good: Much less writing, consistent reads.

31. WORKLOADSWORKLOADS
ML facts / computed data / templated data
Sessions :P
Saving the 50% of RAM used in 8k+ items

32. FUTUREFUTURE

33. JBOD [JUST A BUNCH OFJBOD [JUST A BUNCH OF
DEVICES]DEVICES]
memcached -o
ext_path=/m/f:64g,ext_path=/m2/f:64g

34. TIERED STORAGETIERED STORAGE
github.com/memcached/memcached/pull/432
ext_path=/m/f:64g:compact
ext_path=/m/f:64g:lowttl

35. PERSISTENT MEMORYPERSISTENT MEMORY
HTABLE VALUES

36. WRAP UP: PERFORMANCEWRAP UP: PERFORMANCE

37. 99

41. THANKS!THANKS!
memcached.org/blog
@dormando
github.com/memcached/memcached/wiki/Extstore

42. Watch the video with slide
synchronization on InfoQ.com!
https://www.infoq.com/presentations/
nvme-cache