Cassandra Community Webinar August 29th 2013 - In Case Of Emergency, Break Glass

CASSANDRA COMMUNITY WEBINARS AUGUST 2013

IN CASE OF EMERGENCY, BREAK GLASS

Aaron Morton@aaronmorton

Co-Founder & Principal Consultantwww.thelastpickle.com

Licensed under a Creative Commons Attribution-NonCommercial 3.0 New Zealand License

http://www.thelastpickle.com


http://creativecommons.org/licenses/by-nc/3.0/nz/


About The Last PickleWork with clients to deliver and improve

Apache Cassandra based solutions. Apache Cassandra Committer, DataStax MVP,

Hector Maintainer, 6+ years combined Cassandra experience.

Based in New Zealand & Austin, TX.

PlatformTools

ProblemsMaintenance

www.thelastpickle.com



The Platform




The Platform & Clients




The Platform & Running Clients




The Platform & Reality

ConsistencyAvailability

Partition Tolerance




The Platform & Consistency

Strong Consistency(R + W > N)

Eventual Consistency(R + W <= N)www.thelastpickle.com



What Price Consistency?

In a Multi DC cluster QUOURM and EACH_QUOURM involve

cross DC latency.




The Platform & Availability

Maintain Consistency Level UP nodes for each Token Range.




Best Case Failure with N=9 and RF 3, 100% Availability

Replica 1

Replica 2

Replica 3

Range A




Worst Case Failure with N=9 and RF 3, 78% Availability

Range B

Range A




The Platform & Partition Tolerance

A failed node does not create a partition.





Partitions occur when the network fails.




The Storage Engine

Optimised for Writes.




Write Path

Append to Write Ahead Log.(fsync every 10s by default, other options available)




Write Path

Merge new Columns into Memtable.

(Lock free, always in memory.)




Write Path... Later

Asynchronously flush Memtable to a new SSTable on

disk.(May be 10’s or 100’s of MB in size.)




SSTable Files

*-Data.db*-Index.db*-Filter.db

(And others)




Row Fragmentation

SSTable 1foo: dishwasher (ts 10): tomato purple (ts 10): cromulent

SSTable 2foo: frink (ts 20): flayven monkey (ts 10): embiggins

SSTable 3 SSTable 4foo: dishwasher (ts 15): tomacco

SSTable 5




Read Path

Read columns from each SSTable, then merge results.

(Roughly speaking.)




Read Path

Use Bloom Filter to determine if a row key does

not exist in a SSTable.(In memory)




Read Path

Search for prior key in *-Index.db sample.

(In memory)




Read Path

Scan *-Index.db from prior key to find the search key and its’ *-Data.db

offset.(On disk.)




Read Path

Read *-Data.db from offset, all columns or specific

pages.




Read purple, monkey, dishwasher

SSTable 1-Data.dbfoo: dishwasher (ts 10): tomato purple (ts 10): cromulent

SSTable 2-Data.dbfoo: frink (ts 20): flayven monkey (ts 10): embiggins

SSTable 3-Data.db SSTable 4-Data.dbfoo: dishwasher (ts 15): tomacco

SSTable 5-Data.db

Bloom Filter

Index Sample

SSTable 1-Index.db

Bloom Filter

Index Sample

SSTable 2-Index.db

Bloom Filter

Index Sample

SSTable 3-Index.db

Bloom Filter

Index Sample

SSTable 4-Index.db

Bloom Filter

Index Sample

SSTable 5-Index.db

Memory

Disk




Read With Key Cache




SSTable 5-Data.db

Key Cache

Index Sample

SSTable 1-Index.db

Key Cache

Index Sample

SSTable 2-Index.db

Key Cache

Index Sample

SSTable 3-Index.db

Key Cache

Index Sample

SSTable 4-Index.db

Key Cache

Index Sample

SSTable 5-Index.db

Memory

Disk

Bloom Filter Bloom Filter Bloom Filter Bloom Filter Bloom Filter




Read with Row CacheRow Cache




SSTable 5-Data.db

Key Cache

Index Sample

SSTable 1-Index.db

Key Cache

Index Sample

SSTable 2-Index.db

Key Cache

Index Sample

SSTable 3-Index.db

Key Cache

Index Sample

SSTable 4-Index.db

Key Cache

Index Sample

SSTable 5-Index.db

Memory

Disk

Bloom Filter Bloom Filter Bloom Filter Bloom Filter Bloom Filter




Performant Reads

Design queries to read from a small number of SSTables.




Performant Reads

Read a small number of named columns or a slice of

columns.




Performant Reads

Design data model to support current application

requirements.




PlatformTools

ProblemsMaintenance




Logging

Configure via log4j-server.properties

and StorageServiceMBean




DEBUG Logging For One Class

log4j.logger.org.apache.cassandra.thrift.CassandraServer=DEBUG




Reading LogsINFO [OptionalTasks:1] 2013-04-20 14:03:50,787 MeteredFlusher.java (line 62) flushing high-traffic column family CFS(Keyspace='KS1', ColumnFamily='CF1') (estimated 403858136 bytes)

INFO [OptionalTasks:1] 2013-04-20 14:03:50,787 ColumnFamilyStore.java (line 634) Enqueuing flush of Memtable-CF1@1333396270(145839277/403858136 serialized/live bytes, 1742365 ops)

INFO [FlushWriter:42] 2013-04-20 14:03:50,788 Memtable.java (line 266) Writing Memtable-CF1@1333396270(145839277/403858136 serialized/live bytes, 1742365 ops)




GC Logscassandra-env.sh

# GC logging options -- uncomment to enable# JVM_OPTS="$JVM_OPTS -XX:+PrintGCDetails"# JVM_OPTS="$JVM_OPTS -XX:+PrintGCDateStamps"# JVM_OPTS="$JVM_OPTS -XX:+PrintHeapAtGC"# JVM_OPTS="$JVM_OPTS -XX:+PrintTenuringDistribution"# JVM_OPTS="$JVM_OPTS -XX:+PrintGCApplicationStoppedTime"# JVM_OPTS="$JVM_OPTS -XX:+PrintPromotionFailure"# JVM_OPTS="$JVM_OPTS -XX:PrintFLSStatistics=1"# JVM_OPTS="$JVM_OPTS -Xloggc:/var/log/cassandra/gc-`date +%s`.log"




ParNew GC Starting

{Heap before GC invocations=224115 (full 111): par new generation total 873856K, used 717289K ...) eden space 699136K, 100% used ...) from space 174720K, 10% used ...) to space 174720K, 0% used ...)




Tenuring Distribution

240217.053: [ParNewDesired survivor size 89456640 bytes, new threshold 4 (max 4)- age 1: 22575936 bytes, 22575936 total- age 2: 350616 bytes, 22926552 total- age 3: 4380888 bytes, 27307440 total- age 4: 1155104 bytes, 28462544 total




ParNew GC Finishing

Heap after GC invocations=224116 (full 111): par new generation total 873856K, used 31291K ...) eden space 699136K, 0% used ...) from space 174720K, 17% used ...) to space 174720K, 0% used ...)




nodetool infoToken : 0Gossip active : trueLoad : 130.64 GBGeneration No : 1369334297Uptime (seconds) : 29438Heap Memory (MB) : 3744.27 / 8025.38Data Center : eastRack : rack1Exceptions : 0Key Cache : size 104857584 (bytes), capacity 104857584 (bytes), 25364985 hits, 34874180 requests, 0.734 recent hit rate, 14400 save period in secondsRow Cache : size 0 (bytes), capacity 0...




nodetool ringNote: Ownership information does not include topology, please specify a keyspace. Address DC Rack Status State Load Owns Token 10.1.64.11 east rack1 Up Normal 130.64 GB 12.50% 0 10.1.65.8 west rack1 Up Normal 88.79 GB 0.00% 1 10.1.64.78 east rack1 Up Normal 52.66 GB 12.50% 212...216 10.1.65.181 west rack1 Up Normal 65.99 GB 0.00% 212...217 10.1.66.8 east rack1 Up Normal 64.38 GB 12.50% 425...432 10.1.65.178 west rack1 Up Normal 77.94 GB 0.00% 425...433 10.1.64.201 east rack1 Up Normal 56.42 GB 12.50% 638...648 10.1.65.59 west rack1 Up Normal 74.5 GB 0.00% 638...649 10.1.64.235 east rack1 Up Normal 79.68 GB 12.50% 850...864 10.1.65.16 west rack1 Up Normal 62.05 GB 0.00% 850...865 10.1.66.227 east rack1 Up Normal 106.73 GB 12.50% 106...080 10.1.65.226 west rack1 Up Normal 79.26 GB 0.00% 106...081 10.1.66.247 east rack1 Up Normal 66.68 GB 12.50% 127...295 10.1.65.19 west rack1 Up Normal 102.45 GB 0.00% 127...297 10.1.66.141 east rack1 Up Normal 53.72 GB 12.50% 148...512 10.1.65.253 west rack1 Up Normal 54.25 GB 0.00% 148...513




nodetool ring KS1Address DC Rack Status State Load Effective-Ownership Token 10.1.64.11 east rack1 Up Normal 130.72 GB 12.50% 0 10.1.65.8 west rack1 Up Normal 88.81 GB 12.50% 1 10.1.64.78 east rack1 Up Normal 52.68 GB 12.50% 212...21610.1.65.181 west rack1 Up Normal 66.01 GB 12.50% 212...21710.1.66.8 east rack1 Up Normal 64.4 GB 12.50% 425...43210.1.65.178 west rack1 Up Normal 77.96 GB 12.50% 425...43310.1.64.201 east rack1 Up Normal 56.44 GB 12.50% 638...64810.1.65.59 west rack1 Up Normal 74.57 GB 12.50% 638...64910.1.64.235 east rack1 Up Normal 79.72 GB 12.50% 850...86410.1.65.16 west rack1 Up Normal 62.12 GB 12.50% 850...86510.1.66.227 east rack1 Up Normal 106.72 GB 12.50% 106...08010.1.65.226 west rack1 Up Normal 79.28 GB 12.50% 106...08110.1.66.247 east rack1 Up Normal 66.73 GB 12.50% 127...29510.1.65.19 west rack1 Up Normal 102.47 GB 12.50% 127...29710.1.66.141 east rack1 Up Normal 53.75 GB 12.50% 148...51210.1.65.253 west rack1 Up Normal 54.24 GB 12.50% 148...513




nodetool status$ nodetool statusDatacenter: ams01 (Replication Factor 3)=================Status=Up/Down|/ State=Normal/Leaving/Joining/Moving-- Address Load Tokens Owns Host ID RackUN 10.70.48.23 38.38 GB 256 19.0% 7c5fdfad-63c6-4f37-bb9f-a66271aa3423 RAC1UN 10.70.6.78 58.13 GB 256 18.3% 94e7f48f-d902-4d4a-9b87-81ccd6aa9e65 RAC1UN 10.70.47.126 53.89 GB 256 19.4% f36f1f8c-1956-4850-8040-b58273277d83 RAC1Datacenter: wdc01 (Replication Factor 3)=================Status=Up/Down|/ State=Normal/Leaving/Joining/Moving-- Address Load Tokens Owns Host ID RackUN 10.24.116.66 65.81 GB 256 22.1% f9dba004-8c3d-4670-94a0-d301a9b775a8 RAC1UN 10.55.104.90 63.31 GB 256 21.2% 4746f1bd-85e1-4071-ae5e-9c5baac79469 RAC1UN 10.55.104.27 62.71 GB 256 21.2% 1a55cfd4-bb30-4250-b868-a9ae13d81ae1 RAC1




nodetool cfstatsKeyspace: KS1 Column Family: CF1 SSTable count: 11 Space used (live): 32769179336 Space used (total): 32769179336 Number of Keys (estimate): 73728 Memtable Columns Count: 1069137 Memtable Data Size: 216442624 Memtable Switch Count: 3 Read Count: 95 Read Latency: NaN ms. Write Count: 1039417 Write Latency: 0.068 ms. Bloom Filter False Postives: 345 Bloom Filter False Ratio: 0.00000 Bloom Filter Space Used: 230096 Compacted row minimum size: 150 Compacted row maximum size: 322381140 Compacted row mean size: 2072156




nodetool cfhistograms$nodetool cfhistograms KS1 CF1Offset SSTables Write Latency Read Latency Row Size Column Count1 67264 0 0 0 13315912 19512 0 0 0 42416863 35529 0 0 0 474784...10 10299 1150 0 0 2176812 5475 3569 0 0 399313514 1986 9098 0 0 143477817 258 30916 0 0 36689520 0 52980 0 0 18652424 0 104463 0 0 25439063...179 0 93 1823 1597 1284167215 0 84 3880 1231655 1147150258 0 170 5164 209282 956487




nodetool proxyhistograms$nodetool proxyhistogramsOffset Read Latency Write Latency Range Latency60 0 15 072 0 51 086 0 241 0103 2 2003 0124 9 5798 0149 67 7348 0179 222 6453 0215 184 6071 0258 134 5436 0310 104 4936 0372 89 4997 0446 39 6383 0535 76797 7518 0642 9364748 96065 0770 16406421 152663 0924 7429538 97612 01109 6781835 176829 0




JMX via JConsole




JMX via MX4J




JMX via JMXTERM$ java -jar jmxterm-1.0-alpha-4-uber.jar Welcome to JMX terminal. Type "help" for available commands.$>open localhost:7199#Connection to localhost:7199 is opened$>bean org.apache.cassandra.db:type=StorageService#bean is set to org.apache.cassandra.db:type=StorageService$>info#mbean = org.apache.cassandra.db:type=StorageService#class name = org.apache.cassandra.service.StorageService# attributes %0 - AllDataFileLocations ([Ljava.lang.String;, r) %1 - CommitLogLocation (java.lang.String, r) %2 - CompactionThroughputMbPerSec (int, rw)...# operations %1 - void bulkLoad(java.lang.String p1) %2 - void clearSnapshot(java.lang.String p1,[Ljava.lang.String; p2) %3 - void decommission()




JVM Heap Dump via JMAP

jmap -dump:format=b, file=heap.bin pid




JVM Heap Dump with YourKit




PlatformTools

ProblemsMaintenance




Corrupt SSTable(Very rare.)




Compaction ErrorERROR [CompactionExecutor:36] 2013-04-29 07:50:49,060 AbstractCassandraDaemon.java (line 132) Exception in thread Thread[CompactionExecutor:36,1,main]java.lang.RuntimeException: Last written key DecoratedKey(138024912283272996716128964353306009224, 6138633035613062 2d616666362d376330612d666531662d373738616630636265396535) >= current key DecoratedKey(127065377405949402743383718901402082101, 64323962636163652d646561372d333039322d386166322d663064346132363963386131) writing into *-tmp-hf-7372-Data.db at org.apache.cassandra.io.sstable.SSTableWriter.beforeAppend(SSTableWriter.java:134) at org.apache.cassandra.io.sstable.SSTableWriter.append(SSTableWriter.java:153) at org.apache.cassandra.db.compaction.CompactionTask.execute(CompactionTask.java:160) at org.apache.cassandra.db.compaction.LeveledCompactionTask.execute(LeveledCompactionTask.java:50) at org.apache.cassandra.db.compaction.CompactionManager$2.runMayThrow(CompactionManager.java:164)




Cause

Change in Key Validator or bug in older versions.




Fix

nodetool scrub




Dropped Messages




LogsMessagingService.java (line 658) 173 READ messages dropped in last 5000msStatusLogger.java (line 57) Pool Name Active PendingStatusLogger.java (line 72) ReadStage 32 284StatusLogger.java (line 72) RequestResponseStage 1 254StatusLogger.java (line 72) ReadRepairStage 0 0




nodetool tpstatsMessage type DroppedRANGE_SLICE 0READ_REPAIR 0BINARY 0READ 721MUTATION 1262REQUEST_RESPONSE 196




Causes

Excessive GC.Overloaded IO.

Overloaded Node.Wide Reads / Large Batches.




High Read Latency




nodetool infoToken : 113427455640312814857969558651062452225Gossip active : trueThrift active : trueLoad : 291.13 GBGeneration No : 1368569510Uptime (seconds) : 1022629Heap Memory (MB) : 5213.01 / 8025.38Data Center : 1Rack : 20Exceptions : 0Key Cache : size 104857584 (bytes), capacity 104857584 (bytes), 13436862 hits, 16012159 requests, 0.907 recent hit rate, 14400 save period in secondsRow Cache : size 0 (bytes), capacity 0 (bytes), 0 hits, 0 requests, NaN recent hit rate, 0 save period in seconds




nodetool cfstats Column Family: page_views SSTable count: 17 Space used (live): 289942843592 Space used (total): 289942843592 Number of Keys (estimate): 1071416832 Memtable Columns Count: 2041888 Memtable Data Size: 539015124 Memtable Switch Count: 83 Read Count: 267059 Read Latency: NaN ms. Write Count: 10516969 Write Latency: 0.054 ms. Pending Tasks: 0 Bloom Filter False Positives: 128586 Bloom Filter False Ratio: 0.00000 Bloom Filter Space Used: 802906184 Compacted row minimum size: 447 Compacted row maximum size: 3973 Compacted row mean size: 867




nodetool cfhistograms KS1 CF1Offset SSTables Write Latency Read Latency Row Size Column Count1 178437 0 0 0 02 20042 0 0 0 03 15275 0 0 0 04 11632 0 0 0 05 4771 0 0 0 06 4942 0 0 0 07 5540 0 0 0 08 4967 0 0 0 010 10682 0 0 0 28415512 8355 0 0 0 1537250814 1961 0 0 0 13795909617 322 3 0 0 62573393020 61 253 0 0 25295354724 53 15114 0 0 3910971829 18 255730 0 0 035 1 1532619 0 0 0...




nodetool cfhistograms KS1 CF1Offset SSTables Write Latency Read Latency Row Size Column Count446 0 120 233 0 0535 0 155 261 21361 0642 0 127 284 19082720 0770 0 88 218 498648801 0924 0 86 2699 504702186 01109 0 22 3157 48714564 01331 0 18 2818 241091 01597 0 15 2155 2165 01916 0 19 2098 7 02299 0 10 1140 56 02759 0 10 1281 0 03311 0 6 1064 0 03973 0 4 676 3 0

...




jmx-term$ java -jar jmxterm-1.0-alpha-4-uber.jar Welcome to JMX terminal. Type "help" for available commands.$>open localhost:7199#Connection to localhost:7199 is opened$>bean org.apache.cassandra.db:columnfamily=CF2,keyspace=KS2,type=ColumnFamilies#bean is set to org.apache.cassandra.db:columnfamily=CF2,keyspace=KS2,type=ColumnFamilies$>get BloomFilterFalseRatio#mbean = org.apache.cassandra.db:columnfamily=CF2,keyspace=KS2,type=ColumnFamilies:BloomFilterFalseRatio = 0.5693801541828607;




Back to cfstats

Column Family: page_views Read Count: 270075 Bloom Filter False Positives: 131294




Causebloom_filter_fp_chance had been set to 0.1

to reduce memory requirements when storing 1+ Billion rows per Node.




FixChanged read queries to select by column

name to limit SSTables per query.

Long term, migrate to Cassandra v1.2 for off heap Bloom Filters.




GC Problems




WARN

WARN [ScheduledTasks:1] 2013-03-29 18:40:48,158 GCInspector.java (line 145) Heap is 0.9355130159566108 full. You may need to reduce memtable and/or cache sizes.

INFO [ScheduledTasks:1] 2013-03-26 16:36:06,383 GCInspector.java (line 122) GC for ConcurrentMarkSweep: 207 ms for 1 collections, 10105891032 used; max is 13591642112

INFO [ScheduledTasks:1] 2013-03-28 22:18:17,113 GCInspector.java (line 122) GC for ParNew: 256 ms for 1 collections, 6504905688 used; max is 13591642112




Serious GC ProblemsINFO [ScheduledTasks:1] 2013-04-30 23:21:11,959 GCInspector.java (line 122) GC for ParNew: 1115 ms for 1 collections, 9355247296 used; max is 12801015808




Flapping NodeINFO [GossipTasks:1] 2013-03-28 17:42:07,944 Gossiper.java (line 830) InetAddress /10.1.20.144 is now dead.INFO [GossipStage:1] 2013-03-28 17:42:54,740 Gossiper.java (line 816) InetAddress /10.1.20.144 is now UPINFO [GossipTasks:1] 2013-03-28 17:46:00,585 Gossiper.java (line 830) InetAddress /10.1.20.144 is now dead.INFO [GossipStage:1] 2013-03-28 17:46:13,855 Gossiper.java (line 816) InetAddress /10.1.20.144 is now UPINFO [GossipStage:1] 2013-03-28 17:48:48,966 Gossiper.java (line 830) InetAddress /10.1.20.144 is now dead.




“GC Problems are the result of workload and configuration.”

Aaron Morton, Just Now.




Workload Correlation?

Look for wide rows, large writes, wide reads, un-

bounded multi row reads or writes.




Compaction Correlation?Slow down Compaction to improve stability.concurrent_compactors: 2compaction_throughput_mb_per_sec: 8in_memory_compaction_limit_in_mb: 32

(Monitor and reverse when resolved.)




GC Logging InsightsSlow down rate of tenuring and enable full

GC logging.

HEAP_NEWSIZE="1200M"

JVM_OPTS="$JVM_OPTS -XX:SurvivorRatio=4" JVM_OPTS="$JVM_OPTS -XX:MaxTenuringThreshold=4"




GC’ing Objects in ParNew {Heap before GC invocations=7937 (full 205): par new generation total 1024000K, used 830755K ...) eden space 819200K, 100% used ...) from space 204800K, 5% used ...) to space 204800K, 0% used ...)

Desired survivor size 104857600 bytes, new threshold 4 (max 4)- age 1: 8090240 bytes, 8090240 total- age 2: 565016 bytes, 8655256 total- age 3: 330152 bytes, 8985408 total- age 4: 657840 bytes, 9643248 total




GC’ing Objects in ParNew{Heap before GC invocations=7938 (full 205): par new generation total 1024000K, used 835015K ...) eden space 819200K, 100% used ...) from space 204800K, 7% used ...) to space 204800K, 0% used ...)

Desired survivor size 104857600 bytes, new threshold 4 (max 4)- age 1: 1315072 bytes, 1315072 total- age 2: 541072 bytes, 1856144 total- age 3: 499432 bytes, 2355576 total- age 4: 316808 bytes, 2672384 total




Cause

Nodes had wide rows & 1.3+ Billion rows and 3+GB of

Bloom Filters.(Using older bloom_filter_fp_chance of 0.000744.)




Fix

Increased FP chance to 0.1 on one CF’s and .01 on others.

(One CF reduced from 770MB to 170MB of Bloom Filters.)




Fix

Increased index_interval from 128

to 512.(Increased key_cache_size_in_mb to 200.)




Fix

MAX_HEAP_SIZE="8G"HEAP_NEWSIZE="1000M"-XX:SurvivorRatio=4" -XX:MaxTenuringThreshold=2"




PlatformTools

ProblemsMaintenance




Maintenance

Expand to Multi DC




Expand to Multi DCUpdate Snitch

Update Replication StrategyAdd Nodes

Update Replication FactorRebuild




DC Aware Snitch?

SimpleSnitch puts all nodes in rack1 and datacenter1.




More Snitches?

PropertyFileSnitchRackInferringSnitch




Gossip Based Snitch?

Ec2SnitchEc2MultiRegionSnitchGossipingPropertyFileSnitch*




Changing the Snitch

Do Not change the DC or Rack for an existing node.

(Cassandra will not be able to find your data.)




Moving to the GossipingPropertyFileSnitch

Update cassandra-topology.properties

on existing nodes with existing DC/Rack settings for all existing nodes.

Set default to new DC.www.thelastpickle.com




Update cassandra-rackdc.properties

on existing nodes with existing DC/Rack for the node.





Use a rolling restart to upgrade existing nodes to GossipingPropertyFileSnitch




Got NTS ?

Must use NetworkTopologyStrategy for Multi DC deployments.




SimpleStrategy

Order Token Ranges. Start with range that contains

Row Key.Count to RF.




SimpleStrategy

"foo"




NetworkTopologyStrategy

Order Token Ranges in the DC. Start with range that contains the Row Key.Add first unselected Token Range from each

Rack.Repeat until RF selected.




NetworkTopologyStrategy

"foo"

Rack 1

Rack 2Rack 3




NetworkTopologyStrategy & 1 Rack

"foo"

Rack 1




Changing the Replication Strategy

Be Careful if existing configuration has multiple

Racks.(Cassandra may not be able to find your data.)




Changing the Replication Strategy

Update Keyspace configuration to use NetworkTopologyStrategy with datacenter1:3 and new_dc:0.




Preparing The ClientDisable auto node discovery or use DC

aware methods.

Use LOCAL_QUOURM or EACH_QUOURM.




Expand to Multi DC

Update SnitchUpdate Replication Strategy

Add NodesUpdate Replication Factor

Rebuild




Configuring New NodesAdd auto_bootstrap: false to

cassandra.yaml.Use GossipingPropertyFileSnitch.

Three Seeds from each DC.

(Use cluster_name as a safety.)




Configuring New NodesUpdate cassandra-rackdc.properties

on new nodes with new DC/Rack for the node.

(Ignore cassandra-topology.properties)




Start The New Nodes

New Nodes in the Ring in the new DC without data or

traffic.




Change the Replication Factor

Update Keyspace configuration to use NetworkTopologyStrategy with dataceter1:3 and new_dc:3.




Change the Replication Factor

New DC nodes will start receiving writes from old DC

coordinators.




Y U No Bootstrap?

DC 1 DC 2




nodetool rebuild DC1

DC 1 DC 2




Rebuild Complete

New Nodes now performing Strong Consistency reads.

(If EACH_QUOURM used for writes.)




Summary

Relax.Understand the Platform and

the Tools.Always maintain Availability.




Thanks.




Aaron Morton@aaronmorton

Co-Founder & Principal Consultantwww.thelastpickle.com

Licensed under a Creative Commons Attribution-NonCommercial 3.0 New Zealand License





Cassandra Community Webinar August 29th 2013 - In Case Of Emergency, Break Glass

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Transcript of Cassandra Community Webinar August 29th 2013 - In Case Of Emergency, Break Glass