The internal battle has been fought, and Cassandra is your group's NoSQL platform of choice! Hooray! But now what? This talk will introduce you to all the basic operations concepts you need to know to start your foray into the wonderful world of Cassandra off right. Or even if you have already started but are looking for a solid holistic overview... this is the talk for you!

1. 7 Deadly Sins for Cassandra Ops
Rachel Pedreschi
DSE Evangelist, Datastax

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3. Lust
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#1 USE THE SIMPLE SNITCH

4. So many snitches…
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• SimpleSnitch
• RackInferringSnitch
• PropertyFileSnitch
• GossipingPropertyFileSnitch
• Ec2Snitch
• Ec2MultiRegionSnitch
• GoogleCloudSnitch
• CloudstackSnitch

5. Switching snitches
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If the topology of the network has changed:
-Shut down all the nodes, then restart them.
-Run a sequential repair and nodetool cleanup on each node.
DOWNTIME ALERT!!!!

6. Greed
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#3 NOT UNDERSTANDING
REPAIR

7. Repair options
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repair (default, check your version!)
repair -pr (only repair the primary range)
repair -inc (only new data that has not previously been
repaired)
sequential repair (creates snapshots)
parallel repair uses replica not being repaired

8. Envy
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#3 CHOOSE THE WRONG
COMPACTION STRATEGY FOR
YOUR WORKLOAD

9. Sized Tiered
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SST1 SST1 SST2 SST1 SST2 SST3 SST1 SST2 SST3 SST4 SST5
FLUSH
FLUSH
FLUSH FLUSH
COMPACT
SST5 SST6 SST5 SST6 SST7 SST5 SST6 SST7 SST8 SST5 SST10
FLUSH
FLUSH FLUSH
SST5 SST6 SST7 SST8
FLUSH
SST9
COMPACT
Compacts a set number of SSTables into a single, larger SSTable

10. Leveled
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Level 0
Level 1
10
Level 2
100
Level 3
1,000
Level 4
10,000
Level 5
100,000
… Level 6, 7, etc.

11. Date Tiered
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12. Gluttony
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#4 CHOOSING THE WRONG
HARDWARE

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CPU
RAM
DISK

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• 2 socket, ECC memory
• 16GiB minimum, prefer 32-64GiB, over 128GiB and Linux will need
serious tuning
• SSD where possible, Samsung 840 Pro is a good choice, any
Intel is fine
• NO SAN/NAS, 20ms latency tops
• if you MUST (and please, don’t) dedicate spindles to C* nodes, use
separate network
• Avoid disk configurations targeted at Hadoop, disks are too
slow

15. Sloth
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#5 NOT TUNING YOUR OS

16. /etc/rc.local
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ra=$((2**14))# 16k
ss=$(blockdev --getss /dev/sda)
blockdev --setra $(($ra / $ss)) /dev/sda
echo 128 > /sys/block/sda/queue/nr_requests
echo deadline > /sys/block/sda/queue/scheduler
echo 16384 > /sys/block/md7/md/stripe_cache_size

17. /etc/sysctl.conf
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fs.file-max = 1048576
vm.max_map_count = 1048576
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 65536 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216
vm.swappiness = 1

18. Wrath
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#6 OVER OR UNDERSIZING
YOUR JVM

19. G1 or CMS?
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• Cassandra 8150 vs 7486
• Larger heap? Look into using G1
• Read the Docs
• Test, test and did I mention, test?

20. Pride
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#7 NOT STRESS TESTING

21. cassandra-stress .yaml (>= 2.1)
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1. DDL – for defining your schema
2. Column Distributions – for defining the shape and size of each
column globally and within each partition
3. Insert Distributions – for defining how the data is written during the
stress test
4. DML – for defining how the data is queried during the stress test

22. Recommended Sessions
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DataStax
Making Cassandra Fail (for effective testing)
3:30 Thursday Ballroom H
Pythian
Manage your compactions before they manage you
4:20 Ballroom H
The Last Pickle
Steady State Data Size with Compaction, Tombstones, and TTL
4:20 Great America #2
Wednesday
Crowdstrike, Inc.
Real World DTCS For Operators

23. Thank you
@RachelPedreschi