Speaker(s): Kathryn Erickson, Engineering at DataStax During this session we will discuss varying recommended hardware configurations for DSE. We’ll get right to the point and provide quick and solid recommendations up front. After we get the main points down take a brief tour of the history of database storage and then focus on designing a storage subsystem that won't let you down.

1. 5

2. 4

3. 3

4. 2

5. 1

7. Kathryn
Erickson
Fusion-io

9. CPU
RAM
NETWORK
STORAGE
JAVA

10. CPU
RAM
NETWORK
STORAGE

11. Othe
Cass
Serv
Wha
Scan
Othe
DB’s
Cassandra
Server
Hardware
Other
Stuff
What
Happened
on
Scandal
Last
Week

12. W
W
W W
W W W W

13. W
W
W W
W W W W
Size:
1
1

14. W
W
W W
W W W W
Size:
1
1
Size:
1
2

15. W
W
W W
W W W W
Size:
1
Size:
2
2
2
1

16. W
W
W W
W W W W
Size:
1
Size:
1
2
2
1
Size
2
Size
2
4

17. W
W
W W
W W W W
4

18.
Workload
CPU
RAM
STORAGE
C*/DSE
–
Read
Heavy
Capacity
Driven
4-­‐24
cores
32-­‐256GB
(128
really
but
cache
is
king)
Local
SSD
–
.5
-­‐
2.5TB
C*/DSE
–
Write
Heavy
–
TransacQon
Driven
8-­‐32
cores
32-­‐128GB
Local
SSD
–
1-­‐
3TB
/
spinning
disk
if
you
must
–
.5
–
1TB
DSE
+
SOLR
12-­‐32
cores
128GB
Separate
local
SSD
for
Lucene
and
C*
-­‐
1
–
3TB
DSE
+
SPARK
12-­‐32
cores
128GB
Separate
local
SSD
for
Lucene
and
C*
-­‐
1
–
3TB
*1GbE
is
sufficient
but
many
are
choosing
10GbE
for
future-­‐proofing

19. • WWPDD
–
more
cache
• Cache,
cache,
cache,
cache,
cache,
core-­‐count,
megahertz
• >=20MB
Cache
CPU
12
12
QPI

20. • 4
DIMMs
per
socket
(maybe
2)
• 8-­‐16
GB
DIMMs
is
the
current
sweet-­‐spot
for
$/GB
CPU
RAM
12
12

21. CPU
RAM

22. FRONT
Back
FRONT
Back
FRONT
Back
Single
Rank
Dual
Rank
Quad
Rank
64-­‐bit
64-­‐bit
64-­‐bit

23. 8
8
32GB
32GB
CPU
RAM
E5-­‐2630L
v3
-­‐ DDR4
-­‐ 4
channels
-­‐ 4
x
64-­‐bit
1
x
32GB
(Quad)
Module
2
x
16GB
(Dual)
Modules
4
x
8GB
(Dual)
Modules
4
x
8GB
(Single)
Modules

24. CPU
RAM

25. Metrics
• How
Spinning
Drives
Work
• How
Flash
Works
• Local
Storage
Interfaces
• Graph
It
STORAGE

26. HDD
STORAGE
15K
RPM
HDD
~200
IOPS
~160MB
BW
5ms
Latency
15K
RPM
Disk
Drive
Plaer
Tracks

27. HDD
STORAGE
Short-­‐
Stroking

28. Computers
sQll
have
moving
parts?
Isn’t
there
something
beger?
Maybe
a
sequenQal
write
workload
wouldn’t
be
soooo
bad…
Maybe
I
can
just
get
a
bunch
of
them?
Did
Moore’s
Law
let
us
down?
This
is
a
ridiculous
conversaQon.
Flash
is
cheap
now!

29. • No
Moving
Parts
(Beger
parallelism
thus
beger
BW/IOPS)
• No
Seek
Times
(Low
Latency)
• Lower
Power
• Less
Heat
Produced
(reduced
cooling
cost)
FLASH
STORAGE
SSDs
10K
–
1M
IOPS
400MB-­‐3GB
BW
<200us
Latency

30. • DWPD
–
Overwrites
per
day
over
5
years
• PBW
–
Total
Petabytes
you
can
write
to
the
drive
before
wear
out
MLC
>=1
DWPD

31. Storage
Interfaces
Interface
Speed
SATA
III
.75
Gigabyte
SAS
II
.75
Gigabyte
SAS
III
1.5
Gigabytes
PCIe
Gen
2
x8
4
Gigabytes

32. HDD
STORAGE
–
Average
SATA
Latency
15K
RPM
SAS
7200
RPM
SATA
7200
RPM
SAS

33. FLASH
STORAGE
–
SSD
Average
Latency
PCI-­‐e
SATA

34. STORAGE
–
Average
Latency
SSD
HDD

35. STORAGE
–
Consistent
Latency

36. • CQL
Sizer
-­‐
hgp://
www.sestevez.com/sestevez/
CASTableSizer/
• Use
Opscenter
Capacity
Planner
Storage
Sizing

37. Conclusions
• CPU
-­‐
Get
the
most
Cache
for
your
Cash
• RAM
–
4
DIMMs/CPU
32GB-­‐256GB
Total
• Storage
–
MLC
SSD
–
PCIe
is
Gold
Standard
Acknowledgements
• Al
Tobey,
Mag
Kennedy,
Jon
Erickson