Explore the new IO model and scheduler, which provides fine-tuned balancing of read/write requests based on your disk’s capabilities. This boosts throughput, reduces latency, and minimizes the impact of admin operations like scaling out. Then, we’ll look at how ScyllaDB’s close-to-the-hardware design taps the full power of high-performance cloud computing instances such as the new EC2 I4i instances. Attendees will get a sneak peek at benchmarks comparing ScyllaDB 4.4 on AWS i3.4xl vs. ScyllaDB 5.0 on the new AWS i4.4xl.

1. ScyllaDB V Developer Deep Dive
Series: Performance Enhancements
+ AWS I4i Benchmarking
Pavel Emelyanov, Principal Software Engineer
Peter Corless, Director of Technical Advocacy

2. + Infoworld 2020 Technology of the Year!
+ Founded by designers of KVM Hypervisor
The Database Built for Gamechangers
2
“ScyllaDB stands apart...It’s the rare product
that exceeds my expectations.”
– Martin Heller, InfoWorld contributing editor and reviewer
“For 99.9% of applications, ScyllaDB delivers all the
power a customer will ever need, on workloads that other
databases can’t touch – and at a fraction of the cost of
an in-memory solution.”
– Adrian Bridgewater, Forbes senior contributor
+ Resolves challenges of legacy NoSQL databases
+ >5x higher throughput
+ >20x lower latency
+ >75% TCO savings
+ DBaaS/Cloud, Enterprise and Open Source solutions
+ Proven globally at scale

3. 3
+400 Gamechangers Leverage ScyllaDB
Seamless experiences
across content + devices
Fast computation of flight
pricing
Corporate fleet
management
Real-time analytics
2,000,000 SKU -commerce
management
Real-time location tracking
for friends/family
Video recommendation
management
IoT for industrial
machines
Synchronize browser
properties for millions
Threat intelligence service
using JanusGraph
Real time fraud detection
across 6M transactions/day
Uber scale, mission critical
chat & messaging app
Network security threat
detection
Power ~50M X1 DVRs with
billions of reqs/day
Precision healthcare via
Edison AI
Inventory hub for retail
operations
Property listings and
updates
Unified ML feature store
across the business
Cryptocurrency exchange
app
Geography-based
recommendations
Distributed storage for
distributed ledger tech
Global operations- Avon,
Body Shop + more
Predictable performance for
on sale surges
GPS-based exercise
tracking

4. Today’s Presenters
Pavel Emelyanov Principal Software Engineer
Pavel Emelyanov, principal engineer, ex Linux kernel hacker
now speeding up row cache, tweaking IO scheduler and
helping to pay back a tech debt for components
inter-dependencies.
Speaker Photo
Peter Corless Director of Technical Advocacy
He listens to users’ stories and discovers wisdom in each to share
with other practitioners in the industry at large, whether through
blogs or in technical presentations. He occasionally hosts live
industry events from webinars to online conferences.

5. Agenda
■ IO Scheduler Improvements in
ScyllaDB Open Source 5.0
■ Performance Benchmarking on
AWS EC2 I4i Instances

6. IO Scheduler Improvements in
ScyllaDB Open Source 5.0

7. Why scheduling at all
■ Different components compete for limited resources
■ They have different priorities
■ They have no idea how not to over-consume the resource

8. System architecture

9. RAM Mem0
Biggest problem with disk
CPU0 CPU1 CPU2 … CPUN
Mem1 Mem2 MemN
Disk A Disk B

10. How disk should work
Little’s law
Internal parallelism

11. How disks really work

12. How to schedule IO
+ Get the maximum “concurrency” value
+ With the help of iotune tool
+ Put that much requests into the disk
+ … apply priorities somehow
+ https://www.scylladb.com/2021/04/06/scyllas-new-io-scheduler/

13. How disk does works: I3en

14. How disk does works: I4i

15. Token bucket algorithm (and its math)

16. Current status and future work
+ The algorithm is implemented in Seastar
+ Released with Scylla OpenSource V
+ Works well with “legacy” io_properties.yaml
+ Updated iotune yet to come
+ New per-class metrics reporting the accumulated requests costs
+ On-the-fly tuning of rate limiting factor

17. Scheduler validation

18. Performance Benchmarking on AWS
EC2 I4i Instances

19. AWS EC2 I4i Series (vs. I3)
+ Similar in principle to I3 at lower end
+ Intel Xeon “Ice Lake” @ 3.5 GHz vs.
Intel Xeon E5-2686 v4 (Broadwell)
@ 2.3 GHz (2.7 GHz)
+ 2x RAM of i3.metal vs.
I4i.32xlarge
+ 2x SSD of i3.metal vs.
I4i.32xlarge
+ Nitro SSD + Nitro Hypervisor

20. + ScyllaDB 5.0 on i4i.4xlarge
+ Two factors at play: ScyllaDB 5.0 has faster algorithms, I4i is intrinsically faster hardware
+ Haven’t isolated the specifics for today
+ ScyllaDB 4.4 on i3.4xlarge
+ Cassandra 4.0 on i3.4xlarge
+ Read the full benchmarks from last year here:
https://www.scylladb.com/2021/08/24/apache-cassandra-4-0-vs-scylla-4-4-comparing-performance/
Apples-to-Apples Comparisons

21. 170k vs. 350k = 2x improvement

22. 60k vs. 100k = 67% improvement

23. 80k vs. 110k = 37% improvement

24. 68k vs. 110k = 62% improvement

25. 80k vs. 90k = 12.5% improvement
Reminder: In the real world, not
all rows are created equal

26. 70k vs. 90k = 28% improvement

27. 200k vs. 400k = 100% improvement

28. 240k vs. 440k = 83% improvement

29. 160k vs. 340k = 112% improvement

30. 160k vs. 340k = 112% improvement

31. Poll
How much data do you under management of your
transactional database?

32. Q&A
August 11 August 18
Rust-Based
Drivers and
UDFs with
WebAssembly
Resiliency
and Strong
Consistency
via Raft
UPCOMING DEEP DIVES

33. Thank you
for joining us today.
@scylladb scylladb/
slack.scylladb.com
@scylladb company/scylladb/
scylladb/