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From Yuan Fang <y...@kryptoncloud.com>
Subject Re: Is my cluster normal?
Date Tue, 12 Jul 2016 22:03:09 GMT
Hi Jonathan,

Here is the result:

ubuntu@ip-172-31-44-250:~$ iostat -dmx 2 10
Linux 3.13.0-74-generic (ip-172-31-44-250) 07/12/2016 _x86_64_ (4 CPU)

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.01     2.13    0.74    1.55     0.01     0.02    27.77
    0.00    0.74    0.89    0.66   0.43   0.10
xvdf              0.01     0.58  237.41   52.50    12.90     6.21   135.02
    2.32    8.01    3.65   27.72   0.57  16.63

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     7.50    0.00    2.50     0.00     0.04    32.00
    0.00    1.60    0.00    1.60   1.60   0.40
xvdf              0.00     0.00  353.50    0.00    24.12     0.00   139.75
    0.49    1.37    1.37    0.00   0.58  20.60

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     0.00    0.00    1.00     0.00     0.00     8.00
    0.00    0.00    0.00    0.00   0.00   0.00
xvdf              0.00     2.00  463.50   35.00    30.69     2.86   137.84
    0.88    1.77    1.29    8.17   0.60  30.00

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     0.00    0.00    1.00     0.00     0.00     8.00
    0.00    0.00    0.00    0.00   0.00   0.00
xvdf              0.00     0.00   99.50   36.00     8.54     4.40   195.62
    1.55    3.88    1.45   10.61   1.06  14.40

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     5.00    0.00    1.50     0.00     0.03    34.67
    0.00    1.33    0.00    1.33   1.33   0.20
xvdf              0.00     1.50  703.00  195.00    48.83    23.76   165.57
    6.49    8.36    1.66   32.51   0.55  49.80

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     0.00    0.00    1.00     0.00     0.04    72.00
    0.00    0.00    0.00    0.00   0.00   0.00
xvdf              0.00     2.50  149.50   69.50    10.12     6.68   157.14
    0.74    3.42    1.18    8.23   0.51  11.20

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     5.00    0.00    2.50     0.00     0.03    24.00
    0.00    0.00    0.00    0.00   0.00   0.00
xvdf              0.00     0.00   61.50   22.50     5.36     2.75   197.64
    0.33    3.93    1.50   10.58   0.88   7.40

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     0.00    0.00    0.50     0.00     0.00     8.00
    0.00    0.00    0.00    0.00   0.00   0.00
xvdf              0.00     0.00  375.00    0.00    24.84     0.00   135.64
    0.45    1.20    1.20    0.00   0.57  21.20

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     1.00    0.00    6.00     0.00     0.03     9.33
    0.00    0.00    0.00    0.00   0.00   0.00
xvdf              0.00     0.00  542.50   23.50    35.08     2.83   137.16
    0.80    1.41    1.15    7.23   0.49  28.00

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     3.50    0.50    1.50     0.00     0.02    24.00
    0.00    0.00    0.00    0.00   0.00   0.00
xvdf              0.00     1.50  272.00  153.50    16.18    18.67   167.73
   14.32   33.66    1.39   90.84   0.81  34.60



On Tue, Jul 12, 2016 at 12:34 PM, Jonathan Haddad <jon@jonhaddad.com> wrote:

> When you have high system load it means your CPU is waiting for
> *something*, and in my experience it's usually slow disk.  A disk connected
> over network has been a culprit for me many times.
>
> On Tue, Jul 12, 2016 at 12:33 PM Jonathan Haddad <jon@jonhaddad.com>
> wrote:
>
>> Can do you do:
>>
>> iostat -dmx 2 10
>>
>>
>>
>> On Tue, Jul 12, 2016 at 11:20 AM Yuan Fang <yuan@kryptoncloud.com> wrote:
>>
>>> Hi Jeff,
>>>
>>> The read being low is because we do not have much read operations right
>>> now.
>>>
>>> The heap is only 4GB.
>>>
>>> MAX_HEAP_SIZE=4GB
>>>
>>> On Thu, Jul 7, 2016 at 7:17 PM, Jeff Jirsa <jeff.jirsa@crowdstrike.com>
>>> wrote:
>>>
>>>> EBS iops scale with volume size.
>>>>
>>>>
>>>>
>>>> A 600G EBS volume only guarantees 1800 iops – if you’re exhausting
>>>> those on writes, you’re going to suffer on reads.
>>>>
>>>>
>>>>
>>>> You have a 16G server, and probably a good chunk of that allocated to
>>>> heap. Consequently, you have almost no page cache, so your reads are going
>>>> to hit the disk. Your reads being very low is not uncommon if you have no
>>>> page cache – the default settings for Cassandra (64k compression chunks)
>>>> are really inefficient for small reads served off of disk. If you drop the
>>>> compression chunk size (4k, for example), you’ll probably see your read
>>>> throughput increase significantly, which will give you more iops for
>>>> commitlog, so write throughput likely goes up, too.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *From: *Jonathan Haddad <jon@jonhaddad.com>
>>>> *Reply-To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
>>>> *Date: *Thursday, July 7, 2016 at 6:54 PM
>>>> *To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
>>>> *Subject: *Re: Is my cluster normal?
>>>>
>>>>
>>>>
>>>> What's your CPU looking like? If it's low, check your IO with iostat or
>>>> dstat. I know some people have used Ebs and say it's fine but ive been
>>>> burned too many times.
>>>>
>>>> On Thu, Jul 7, 2016 at 6:12 PM Yuan Fang <yuan@kryptoncloud.com> wrote:
>>>>
>>>> Hi Riccardo,
>>>>
>>>>
>>>>
>>>> Very low IO-wait. About 0.3%.
>>>>
>>>> No stolen CPU. It is a casssandra only instance. I did not see any
>>>> dropped messages.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ubuntu@cassandra1:/mnt/data$ nodetool tpstats
>>>>
>>>> Pool Name                    Active   Pending      Completed   Blocked
>>>>  All time blocked
>>>>
>>>> MutationStage                     1         1      929509244         0
>>>>                 0
>>>>
>>>> ViewMutationStage                 0         0              0         0
>>>>                 0
>>>>
>>>> ReadStage                         4         0        4021570         0
>>>>                 0
>>>>
>>>> RequestResponseStage              0         0      731477999         0
>>>>                 0
>>>>
>>>> ReadRepairStage                   0         0         165603         0
>>>>                 0
>>>>
>>>> CounterMutationStage              0         0              0         0
>>>>                 0
>>>>
>>>> MiscStage                         0         0              0         0
>>>>                 0
>>>>
>>>> CompactionExecutor                2        55          92022         0
>>>>                 0
>>>>
>>>> MemtableReclaimMemory             0         0           1736         0
>>>>                 0
>>>>
>>>> PendingRangeCalculator            0         0              6         0
>>>>                 0
>>>>
>>>> GossipStage                       0         0         345474         0
>>>>                 0
>>>>
>>>> SecondaryIndexManagement          0         0              0         0
>>>>                 0
>>>>
>>>> HintsDispatcher                   0         0              4         0
>>>>                 0
>>>>
>>>> MigrationStage                    0         0             35         0
>>>>                 0
>>>>
>>>> MemtablePostFlush                 0         0           1973         0
>>>>                 0
>>>>
>>>> ValidationExecutor                0         0              0         0
>>>>                 0
>>>>
>>>> Sampler                           0         0              0         0
>>>>                 0
>>>>
>>>> MemtableFlushWriter               0         0           1736         0
>>>>                 0
>>>>
>>>> InternalResponseStage             0         0           5311         0
>>>>                 0
>>>>
>>>> AntiEntropyStage                  0         0              0         0
>>>>                 0
>>>>
>>>> CacheCleanupExecutor              0         0              0         0
>>>>                 0
>>>>
>>>> Native-Transport-Requests       128       128      347508531         2
>>>>          15891862
>>>>
>>>>
>>>>
>>>> Message type           Dropped
>>>>
>>>> READ                         0
>>>>
>>>> RANGE_SLICE                  0
>>>>
>>>> _TRACE                       0
>>>>
>>>> HINT                         0
>>>>
>>>> MUTATION                     0
>>>>
>>>> COUNTER_MUTATION             0
>>>>
>>>> BATCH_STORE                  0
>>>>
>>>> BATCH_REMOVE                 0
>>>>
>>>> REQUEST_RESPONSE             0
>>>>
>>>> PAGED_RANGE                  0
>>>>
>>>> READ_REPAIR                  0
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, Jul 7, 2016 at 5:24 PM, Riccardo Ferrari <ferrarir@gmail.com>
>>>> wrote:
>>>>
>>>> Hi Yuan,
>>>>
>>>>
>>>>
>>>> You machine instance is 4 vcpus that is 4 threads (not cores!!!), aside
>>>> from any Cassandra specific discussion a system load of 10 on a 4 threads
>>>> machine is way too much in my opinion. If that is the running average
>>>> system load I would look deeper into system details. Is that IO wait? Is
>>>> that CPU Stolen? Is that a Cassandra only instance or are there other
>>>> processes pushing the load?
>>>>
>>>> What does your "nodetool tpstats" say? Hoe many dropped messages do you
>>>> have?
>>>>
>>>>
>>>>
>>>> Best,
>>>>
>>>>
>>>>
>>>> On Fri, Jul 8, 2016 at 12:34 AM, Yuan Fang <yuan@kryptoncloud.com>
>>>> wrote:
>>>>
>>>> Thanks Ben! For the post, it seems they got a little better but similar
>>>> result than i did. Good to know it.
>>>>
>>>> I am not sure if a little fine tuning of heap memory will help or not.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, Jul 7, 2016 at 2:58 PM, Ben Slater <ben.slater@instaclustr.com>
>>>> wrote:
>>>>
>>>> Hi Yuan,
>>>>
>>>>
>>>>
>>>> You might find this blog post a useful comparison:
>>>>
>>>>
>>>> https://www.instaclustr.com/blog/2016/01/07/multi-data-center-apache-spark-and-apache-cassandra-benchmark/
>>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.instaclustr.com_blog_2016_01_07_multi-2Ddata-2Dcenter-2Dapache-2Dspark-2Dand-2Dapache-2Dcassandra-2Dbenchmark_&d=CwMFaQ&c=08AGY6txKsvMOP6lYkHQpPMRA1U6kqhAwGa8-0QCg3M&r=yfYEBHVkX6l0zImlOIBID0gmhluYPD5Jje-3CtaT3ow&m=Ltg5YUTZbI4Ixf7UjzKW636Llz6zXXurTveCLptZwio&s=MU4-NWBjvVO95HnxQtkYk4xkApq4X4IiVy8tPCgj4KU&e=>
>>>>
>>>>
>>>>
>>>> Although the focus is on Spark and Cassandra and multi-DC there are
>>>> also some single DC benchmarks of m4.xl
>>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__m4.xl&d=CwQFaQ&c=08AGY6txKsvMOP6lYkHQpPMRA1U6kqhAwGa8-0QCg3M&r=yfYEBHVkX6l0zImlOIBID0gmhluYPD5Jje-3CtaT3ow&m=Ltg5YUTZbI4Ixf7UjzKW636Llz6zXXurTveCLptZwio&s=m3DfZk3YOaf0W2OvACsqDWXp-vdlkP-cC0WnEouZwkk&e=>
>>>> clusters plus some discussion of how we went about benchmarking.
>>>>
>>>>
>>>>
>>>> Cheers
>>>>
>>>> Ben
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Fri, 8 Jul 2016 at 07:52 Yuan Fang <yuan@kryptoncloud.com> wrote:
>>>>
>>>> Yes, here is my stress test result:
>>>>
>>>> Results:
>>>>
>>>> op rate                   : 12200 [WRITE:12200]
>>>>
>>>> partition rate            : 12200 [WRITE:12200]
>>>>
>>>> row rate                  : 12200 [WRITE:12200]
>>>>
>>>> latency mean              : 16.4 [WRITE:16.4]
>>>>
>>>> latency median            : 7.1 [WRITE:7.1]
>>>>
>>>> latency 95th percentile   : 38.1 [WRITE:38.1]
>>>>
>>>> latency 99th percentile   : 204.3 [WRITE:204.3]
>>>>
>>>> latency 99.9th percentile : 465.9 [WRITE:465.9]
>>>>
>>>> latency max               : 1408.4 [WRITE:1408.4]
>>>>
>>>> Total partitions          : 1000000 [WRITE:1000000]
>>>>
>>>> Total errors              : 0 [WRITE:0]
>>>>
>>>> total gc count            : 0
>>>>
>>>> total gc mb               : 0
>>>>
>>>> total gc time (s)         : 0
>>>>
>>>> avg gc time(ms)           : NaN
>>>>
>>>> stdev gc time(ms)         : 0
>>>>
>>>> Total operation time      : 00:01:21
>>>>
>>>> END
>>>>
>>>>
>>>>
>>>> On Thu, Jul 7, 2016 at 2:49 PM, Ryan Svihla <rs@foundev.pro> wrote:
>>>>
>>>> Lots of variables you're leaving out.
>>>>
>>>>
>>>>
>>>> Depends on write size, if you're using logged batch or not, what
>>>> consistency level, what RF, if the writes come in bursts, etc, etc.
>>>> However, that's all sort of moot for determining "normal" really you need
a
>>>> baseline as all those variables end up mattering a huge amount.
>>>>
>>>>
>>>>
>>>> I would suggest using Cassandra stress as a baseline and go from there
>>>> depending on what those numbers say (just pick the defaults).
>>>>
>>>> Sent from my iPhone
>>>>
>>>>
>>>> On Jul 7, 2016, at 4:39 PM, Yuan Fang <yuan@kryptoncloud.com> wrote:
>>>>
>>>> yes, it is about 8k writes per node.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, Jul 7, 2016 at 2:18 PM, daemeon reiydelle <daemeonr@gmail.com>
>>>> wrote:
>>>>
>>>> Are you saying 7k writes per node? or 30k writes per node?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *.......Daemeon C.M. ReiydelleUSA (+1) 415.501.0198
>>>> <%28%2B1%29%20415.501.0198>London (+44) (0) 20 8144 9872
>>>> <%28%2B44%29%20%280%29%2020%208144%209872>*
>>>>
>>>>
>>>>
>>>> On Thu, Jul 7, 2016 at 2:05 PM, Yuan Fang <yuan@kryptoncloud.com>
>>>> wrote:
>>>>
>>>> writes 30k/second is the main thing.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, Jul 7, 2016 at 1:51 PM, daemeon reiydelle <daemeonr@gmail.com>
>>>> wrote:
>>>>
>>>> Assuming you meant 100k, that likely for something with 16mb of storage
>>>> (probably way small) where the data is more that 64k hence will not fit
>>>> into the row cache.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *.......Daemeon C.M. ReiydelleUSA (+1) 415.501.0198
>>>> <%28%2B1%29%20415.501.0198>London (+44) (0) 20 8144 9872
>>>> <%28%2B44%29%20%280%29%2020%208144%209872>*
>>>>
>>>>
>>>>
>>>> On Thu, Jul 7, 2016 at 1:25 PM, Yuan Fang <yuan@kryptoncloud.com>
>>>> wrote:
>>>>
>>>>
>>>>
>>>> I have a cluster of 4 m4.xlarge nodes(4 cpus and 16 gb memory and 600GB
>>>> ssd EBS).
>>>>
>>>> I can reach a cluster wide write requests of 30k/second and read
>>>> request about 100/second. The cluster OS load constantly above 10. Are
>>>> those normal?
>>>>
>>>>
>>>>
>>>> Thanks!
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Best,
>>>>
>>>>
>>>>
>>>> Yuan
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> ————————
>>>>
>>>> Ben Slater
>>>>
>>>> Chief Product Officer
>>>>
>>>> Instaclustr: Cassandra + Spark - Managed | Consulting | Support
>>>>
>>>> +61 437 929 798
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>

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