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From Shing Hing Man <mat...@yahoo.com>
Subject Re: Apache Cassandra 2.1.0 : cassandra-stress performance discrepancy between SSD and SATA drive
Date Mon, 29 Sep 2014 18:49:19 GMT
I have run a sysbench  file io test on my home PC and office PC. The result is  given below.
The result shows my office PC (with a SSD) is about 3 times more performant than my home PC
(with a sata hard disk).

Home PC :

gauss:~> sysbench --test=fileio --file-total-size=50G prepare
sysbench 0.5:  multi-threaded system evaluation benchmark

128 files, 409600Kb each, 51200Mb total
Creating files for the test...
Extra file open flags: 0
Creating file test_file.0
Creating file test_file.1
Creating file test_file.2
.........
Creating file test_file.125
Creating file test_file.126
Creating file test_file.127
53687091200 bytes written in 626.30 seconds (81.75 MB/sec).
matmsh@gauss:~> sysbench --test=fileio --file-total-size=50G --file-test-mode=rndrw --init-rng=on
--max-time=300 --max-requests=0 run
sysbench 0.5:  multi-threaded system evaluation benchmark

Running the test with following options:
Number of threads: 1
Random number generator seed is 0 and will be ignored


Extra file open flags: 0
128 files, 400Mb each
50Gb total file size
Block size 16Kb
Number of IO requests: 0
Read/Write ratio for combined random IO test: 1.50
Periodic FSYNC enabled, calling fsync() each 100 requests.
Calling fsync() at the end of test, Enabled.
Using synchronous I/O mode
Doing random r/w test
Threads started!

Operations performed:  14521 reads, 9680 writes, 30976 Other = 55177 Total
Read 226.89Mb  Written 151.25Mb  Total transferred 378.14Mb  (1.2605Mb/sec)
   80.67 Requests/sec executed

General statistics:
    total time:                          300.0030s
    total number of events:              24201
    total time taken by event execution: 186.0749s
    response time:
         min:                                  0.00ms
         avg:                                  7.69ms
         max:                                132.43ms
         approx.  95 percentile:              19.57ms

Threads fairness:
    events (avg/stddev):           24201.0000/0.00
    execution time (avg/stddev):   186.0749/0.00

gauss:~> 
===============================
Office PC :
shing@cauchy:~> sysbench --test=fileio --file-total-size=50G prepare
sysbench 0.5:  multi-threaded system evaluation benchmark

128 files, 409600Kb each, 51200Mb total
Creating files for the test...
Extra file open flags: 0
Creating file test_file.0
Creating file test_file.1
Creating file test_file.2
Creating file test_file.3
...Creating file test_file.122
Creating file test_file.123
Creating file test_file.124
Creating file test_file.125
Creating file test_file.126
Creating file test_file.127
53687091200 bytes written in 175.55 seconds (291.66 MB/sec).
cauchy:~> sysbench --test=fileio --file-total-size=50G --file-test-mode=rndrw --init-rng=on
--max-time=300 --max-requests=0 run
sysbench 0.5:  multi-threaded system evaluation benchmark

Running the test with following options:
Number of threads: 1
Random number generator seed is 0 and will be ignored

Extra file open flags: 0
128 files, 400Mb each
50Gb total file size
Block size 16Kb
Number of IO requests: 0
Read/Write ratio for combined random IO test: 1.50
Periodic FSYNC enabled, calling fsync() each 100 requests.
Calling fsync() at the end of test, Enabled.
Using synchronous I/O mode
Doing random r/w test
Threads started!

Operations performed:  43020 reads, 28680 writes, 91723 Other = 163423 Total
Read 672.19Mb  Written 448.12Mb  Total transferred 1.0941Gb  (3.7344Mb/sec)
  239.00 Requests/sec executed

General statistics:
    total time:                          300.0007s
    total number of events:              71700
    total time taken by event execution: 7.5550s
    response time:
         min:                                  0.00ms
         avg:                                  0.11ms
         max:                                 12.89ms
         approx.  95 percentile:               0.22ms

Threads fairness:
    events (avg/stddev):           71700.0000/0.00
    execution time (avg/stddev):   7.5550/0.00
=======================



Shing



On Saturday, 27 September 2014, 10:24, Shing Hing Man <matmsh@yahoo.com> wrote:
 


Hi Kevin,
   Thanks for the reply !
I do not know the exact brand of SSD in my office PC. But the SSD is  only 1 year old,  and
it is far from full. 

On both of office PC and home PC, I untared Apache Cassandra 2.1.0 and then 

        run "cassandra -f " with the default config,   then

        run cassandra-stress 

Both PCs  have Oracle Java 1.7.0_40.

I have noticed there are some parameters for SSD in cassandra.yaml, which I have adjusted,
but with no improvement. 


It  puzzles me Cassandra on  my office PC, with far better hardware,  could be 100% slower
than my home PC. 



Shing







On Saturday, 27 September 2014, 5:12, Kevin Burton <burton@spinn3r.com> wrote:
 


What SSD was it?  There are a lot of variability in terms of SSD performance.

1.  Is it a new vs old SSD?  Old SSDs can become slower if they’re really worn out

2.  was the office SSD near capacity holding other data?

3.  what models were they?

SSD != SSD… there is a massive amount of performance variability out there.

… also … more data is needed.  JDK versions the same?  cassandra versions the same?

what about the config?


On Fri, Sep 26, 2014 at 2:39 PM, Shing Hing Man <matmsh@yahoo.com> wrote:

Hi,
>  I have run   cassandra-stress write and  cassandra-stress read  on my office PC and
on my home PC. 
>
>
>Office PC : Intel Core i7-4479, 8  virtual core, 16G RAM, 500G SSD Home PC : Intel Xeon
E3-1230V3, 8 virtual core,  8G RAM, 500G SATA disk.
>
>
>From the cassandra-stress result (please see below), it seems  Cassandra is more than
100% performant on my home PC than the office PC.   I am expecting the other way around, as
my office PC has much  better hardware. 
>
>
>
>Office : Intel Core i7-4479, 9  virtual cores, 16G RAM, 500G SSDcauchy:~/installed/cassandra/tools/bin>
./cassandra-stress write 
>Running with 8 threadCount
>Results:
>op rate                   : 11264
>partition rate            : 11264
>row rate                  : 11264
>latency mean              : 0.7
>latency median            : 0.4
>latency 95th percentile   : 0.9
>latency 99th percentile   : 1.6
>latency 99.9th percentile : 5.3
>latency max               : 325.3
>Total operation time      : 00:02:40
>
>
>
>
>cauchy:~/installed/cassandra/tools/bin> ./cassandra-stress read 
>Running with 8 threadCount
>Results:
>op rate                   : 13702
>partition rate            : 13702
>row rate                  : 13702
>latency mean              : 0.5
>latency median            : 0.5
>latency 95th percentile   : 0.8
>latency 99th percentile   : 1.4
>latency 99.9th percentile : 3.4
>latency max               : 67.1
>Total operation time      : 00:00:30
>
>
>---------------------------------------------------
>--------------------------------------------------
>
>Home : Intel Xeon E3-1230V3, 8 virtual core,  8G RAM, 500G SATA disk.
>
>
>matmsh@gauss:~/installed/cassandra/tools/bin> ./cassandra-stress write
>Running with 8 threadCount
>
>
>Results:
>op rate                   : 25181
>partition rate            : 25181
>row rate                  : 25181
>latency mean              : 0.3
>latency median            : 0.2
>latency 95th percentile   : 0.3
>latency 99th percentile   : 0.5
>latency 99.9th percentile : 16.7
>latency max               : 331.0
>Total operation time      : 00:03:24
>
>
>gauss:~/installed/cassandra/tools/bin> ./cassandra-stress read
>Results:
>op rate                   : 35338
>partition rate            : 35338
>row rate                  : 35338
>latency mean              : 0.2
>latency median            : 0.2
>latency 95th percentile   : 0.3
>latency 99th percentile   : 0.4
>latency 99.9th percentile : 1.1
>latency max               : 17.7
>Total operation time      : 00:00:30
>
>
>
>
>Is the above result expected ?
>Thanks in advance for any suggestions !
>
>
>Shing
>
>
>
>
>


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