I'm looking for advice for running cassandra 8.+ on a single node. Would love to hear stories about how much RAM you succeeded with, etc.
Currently we are running with a 4GB heap size. Hardware is 4 cores and 8GB
physical memory. We're not opposed to going to 16GB of memory or even 32GB.
We have fast 6GBps SAS drives, although currently do not have a dedicated drive
for Commit Log, but we are thinking about trying this out.
Our application has time series data which means our data will get larger over
time, not in all CFs though. We have 7 "hot" CFs but they are probably not
that hot to someone running a sizable cluster. We have 15 CFs total in our
keyspace.
I've already tweaked key cache and in some cases added a large enough row cache
to keep an entire CF in memory where appropriate.
Basically, I'm just curious under this sort of load if we can expect decent
results with a single node as the data gets larger. I know this isn't
necessarily a binary answer, just curious about people's experiences on a
single node.
Thanks,
-Derek
cfstats:
----------------
Keyspace: test
Read Count: 2869777
Read Latency: 1.2266526890416922 ms.
Write Count: 7672036
Write Latency: 0.016663120975970395 ms.
Pending Tasks: 0
Column Family: DocData
SSTable count: 1
Space used (live): 425090
Space used (total): 425090
Number of Keys (estimate): 128
Memtable Columns Count: 0
Memtable Data Size: 0
Memtable Switch Count: 0
Read Count: 162
Read Latency: NaN ms.
Write Count: 0
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 1000
Key cache size: 27
Key cache hit rate: NaN
Row cache: disabled
Compacted row minimum size: 771
Compacted row maximum size: 315852
Compacted row mean size: 18290
Column Family: User
SSTable count: 1
Space used (live): 5368
Space used (total): 5368
Number of Keys (estimate): 128
Memtable Columns Count: 0
Memtable Data Size: 0
Memtable Switch Count: 0
Read Count: 0
Read Latency: NaN ms.
Write Count: 0
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 1000
Key cache size: 0
Key cache hit rate: NaN
Row cache capacity: 1000
Row cache size: 0
Row cache hit rate: NaN
Compacted row minimum size: 447
Compacted row maximum size: 535
Compacted row mean size: 535
Column Family: SMapping
SSTable count: 1
Space used (live): 536900
Space used (total): 536900
Number of Keys (estimate): 768
Memtable Columns Count: 9528
Memtable Data Size: 4646940
Memtable Switch Count: 0
Read Count: 763
Read Latency: NaN ms.
Write Count: 763
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 1000
Key cache size: 763
Key cache hit rate: NaN
Row cache capacity: 1000
Row cache size: 763
Row cache hit rate: NaN
Compacted row minimum size: 447
Compacted row maximum size: 73457
Compacted row mean size: 713
Column Family: LObject
SSTable count: 2
Space used (live): 6945430
Space used (total): 6945430
Number of Keys (estimate): 10752
Memtable Columns Count: 729638
Memtable Data Size: 400799230
Memtable Switch Count: 2
Read Count: 316756
Read Latency: NaN ms.
Write Count: 147028
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 20000
Key cache size: 20000
Key cache hit rate: NaN
Row cache capacity: 20000
Row cache size: 5304
Row cache hit rate: NaN
Compacted row minimum size: 259
Compacted row maximum size: 182785
Compacted row mean size: 661
Column Family: SMeta
SSTable count: 2
Space used (live): 173059487
Space used (total): 343520951
Number of Keys (estimate): 165760
Memtable Columns Count: 442764
Memtable Data Size: 168300272
Memtable Switch Count: 53
Read Count: 2345765
Read Latency: 0.009 ms.
Write Count: 2179885
Write Latency: 0.033 ms.
Pending Tasks: 0
Key cache: disabled
Row cache capacity: 100000
Row cache size: 82940
Row cache hit rate: 1.0
Compacted row minimum size: 925
Compacted row maximum size: 1109
Compacted row mean size: 1109
Column Family: SLookback
SSTable count: 14
Space used (live): 16604796474
Space used (total): 17754314562
Number of Keys (estimate): 2515968
Memtable Columns Count: 49500
Memtable Data Size: 38927091
Memtable Switch Count: 18
Read Count: 194587
Read Latency: 13.929 ms.
Write Count: 200732
Write Latency: 0.011 ms.
Pending Tasks: 0
Key cache capacity: 200000
Key cache size: 200000
Key cache hit rate: 0.2599537318884695
Row cache: disabled
Compacted row minimum size: 311
Compacted row maximum size: 35425
Compacted row mean size: 7338
Column Family: Event
SSTable count: 2
Space used (live): 23480776
Space used (total): 23480776
Number of Keys (estimate): 33280
Memtable Columns Count: 77
Memtable Data Size: 5310
Memtable Switch Count: 1
Read Count: 12
Read Latency: NaN ms.
Write Count: 12
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 10000
Key cache size: 0
Key cache hit rate: NaN
Row cache capacity: 1000
Row cache size: 0
Row cache hit rate: NaN
Compacted row minimum size: 643
Compacted row maximum size: 770
Compacted row mean size: 770
Column Family: SHourly
SSTable count: 3
Space used (live): 847441284
Space used (total): 847441284
Number of Keys (estimate): 496768
Memtable Columns Count: 35256
Memtable Data Size: 67814381
Memtable Switch Count: 3
Read Count: 0
Read Latency: NaN ms.
Write Count: 330520
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 1000
Key cache size: 0
Key cache hit rate: NaN
Row cache: disabled
Compacted row minimum size: 180
Compacted row maximum size: 9887
Compacted row mean size: 1835
Column Family: ConfigSettings
SSTable count: 1
Space used (live): 4854
Space used (total): 4854
Number of Keys (estimate): 128
Memtable Columns Count: 0
Memtable Data Size: 0
Memtable Switch Count: 0
Read Count: 135
Read Latency: 0.007 ms.
Write Count: 0
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 100
Key cache size: 1
Key cache hit rate: NaN
Row cache capacity: 100
Row cache size: 1
Row cache hit rate: 1.0
Compacted row minimum size: 536
Compacted row maximum size: 642
Compacted row mean size: 642
Column Family: SystemMeta
SSTable count: 2
Space used (live): 9258
Space used (total): 9258
Number of Keys (estimate): 256
Memtable Columns Count: 48
Memtable Data Size: 2570
Memtable Switch Count: 1
Read Count: 18
Read Latency: NaN ms.
Write Count: 10
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 100
Key cache size: 1
Key cache hit rate: NaN
Row cache capacity: 100
Row cache size: 1
Row cache hit rate: NaN
Compacted row minimum size: 311
Compacted row maximum size: 372
Compacted row mean size: 372
Column Family: LConfig
SSTable count: 2
Space used (live): 22198
Space used (total): 22198
Number of Keys (estimate): 256
Memtable Columns Count: 3614
Memtable Data Size: 399019
Memtable Switch Count: 1
Read Count: 261
Read Latency: NaN ms.
Write Count: 261
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 1000
Key cache size: 9
Key cache hit rate: 0.0
Row cache capacity: 1000
Row cache size: 9
Row cache hit rate: NaN
Compacted row minimum size: 643
Compacted row maximum size: 770
Compacted row mean size: 770
Column Family: S
SSTable count: 6
Space used (live): 4845200284
Space used (total): 4926197540
Number of Keys (estimate): 496512
Memtable Columns Count: 61093
Memtable Data Size: 116164716
Memtable Switch Count: 26
Read Count: 11318
Read Latency: 76.083 ms.
Write Count: 2215986
Write Latency: 0.008 ms.
Pending Tasks: 0
Key cache capacity: 5000
Key cache size: 5000
Key cache hit rate: 0.0018995517057974318
Row cache: disabled
Compacted row minimum size: 216
Compacted row maximum size: 105778
Compacted row mean size: 10079
Column Family: SLookbackLog
SSTable count: 2
Space used (live): 23988670
Space used (total): 23988670
Number of Keys (estimate): 10496
Memtable Columns Count: 111401
Memtable Data Size: 50531214
Memtable Switch Count: 7
Read Count: 0
Read Latency: NaN ms.
Write Count: 2431579
Write Latency: 0.007 ms.
Pending Tasks: 0
Key cache capacity: 10496
Key cache size: 0
Key cache hit rate: NaN
Row cache capacity: 10496
Row cache size: 0
Row cache hit rate: NaN
Compacted row minimum size: 73
Compacted row maximum size: 20501
Compacted row mean size: 2484
Column Family: Tag
SSTable count: 0
Space used (live): 0
Space used (total): 0
Number of Keys (estimate): 0
Memtable Columns Count: 0
Memtable Data Size: 0
Memtable Switch Count: 0
Read Count: 0
Read Latency: NaN ms.
Write Count: 0
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 1000
Key cache size: 0
Key cache hit rate: NaN
Row cache capacity: 1000
Row cache size: 0
Row cache hit rate: NaN
Compacted row minimum size: 0
Compacted row maximum size: 0
Compacted row mean size: 0
Column Family: SDaily
SSTable count: 1
Space used (live): 60375798
Space used (total): 60375798
Number of Keys (estimate): 166016
Memtable Columns Count: 165260
Memtable Data Size: 8056425
Memtable Switch Count: 0
Read Count: 0
Read Latency: NaN ms.
Write Count: 165260
Write Latency: NaN ms.
Pending Tasks: 0
Key cache capacity: 1000
Key cache size: 0
Key cache hit rate: NaN
Row cache: disabled
Compacted row minimum size: 150
Compacted row maximum size: 446
Compacted row mean size: 284
----------------
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