Jie,

A colleague points out that I typed "40" in one place and "50" in another.  
"40" is the appropriate setting.  

Matthew


On Apr 15, 2014, at 8:41 AM, Matthew Von-Maszewski <[email protected]> wrote:

> Jie,
> 
> 4G ram is small for your ring size and node count.  My first recommendation 
> is that you reduce your ring size to 32 {ring_creation_size, 32}.  Then 
> change the max_open_files setting of eleveldb to 40 {max_open_files, 50} and 
> block_size to 32768 {sst_block_size, 32768}.  These three settings should 
> quickly improve performance … but require you start over with your cluster.
> 
> Active Anti-Entropy has a bug in 1.4.7.  You might as well disable it too:  
> {anti_entropy, {off, []}}.  The recommendation is that you upgrade to 1.4.8.
> 
> Matthew
> 
> 
> 
> 
> On Apr 14, 2014, at 10:10 PM, Jie Lu <[email protected]> wrote:
> 
>> 
>> I also have a problem in performance test of Riak Cluster.
>> ~~~~~~~~~~~~
>> Riak version: 1.4.7
>> OS: openSUSE 11.3
>> RAM: 4G
>> ring size is 64
>> backend: leveldb
>> Nodes in cluster: 6 nodes
>> 
>> ~~~~~~~~~~~~~
>> 
>> I write a key/value with value is 1K bytes, and 25 concurrent  threads on 
>> one client nodes. The test result only 20 ops/s performance. 
>> 
>> Is there any performance benchmark to compare with?
>> 
>> 
>> 
>> 
>> 
>> 
>> On Tue, Apr 15, 2014 at 6:26 AM, Luke Bakken <[email protected]> wrote:
>> Hi Matthew -
>> 
>> Some suggestions:
>> 
>> * Upgrade to Riak 1.4.8
>> 
>> * Test with a ring size of 64
>> 
>> * Use staggered merge windows in your cluster 
>> (http://docs.basho.com/riak/latest/ops/advanced/backends/bitcask/)
>> 
>> * Since you're on dedicated hardware RAID, use the noop scheduler for your 
>> Riak data volumes:
>> 
>> cat /sys/block/sd*/queue/scheduler
>> noop anticipatory deadline [cfq]
>> 
>> * Increase +zdbbl in /etc/riak/vm.args to 96000
>> 
>> Thanks
>> --
>> Luke Bakken
>> CSE
>> [email protected]
>> 
>> 
>> On Mon, Apr 14, 2014 at 2:33 PM, Matthew MacClary 
>> <[email protected]> wrote:
>> I have a persistent issue I am trying to diagnose. In our use of Riak we 
>> have multiple data creators writing into a 7 node cluster. The value size is 
>> a bit large at around 2MB. The behavior I am seeing is that if I delete all 
>> data out of bitcask, then test performance I get fast writes. As I keep 
>> doing the same work of writing to the cluster, then the Riak write times 
>> will start tailing off and getting really bad.
>> 
>> Initial write times seen by my application: 0.5 seconds for 100MB worth of 
>> values (~200MB/s)
>> Subsequent write times: 11 seconds for 100MB worth of values (~9MB/s)
>> 
>> This slow down can happen over roughly 20-40 minutes of writing or about 
>> 200GB worth of key/value pairs written.
>> 
>> I can reset the cluster to get fast performance again by stopping Riak and 
>> deleting the bitcask directories, then starting Riak again. This step is not 
>> feasible for production, but during testing at least the write speed goes up 
>> by 20x.
>> 
>> Watching iostat I see that every few seconds the disk io jumps to ~11%. It 
>> doesn't seem that highly loaded from my cursory look. Watching top I see 
>> that beam.smp runs at around 100 for CPU% or less when heavily loaded. I am 
>> not sure how to tell what it is doing though :-)
>> 
>> Thanks for any suggestions!!
>> 
>> -Matt
>> 
>> 
>> 
>> ================
>> System Description
>> 
>> 
>> avg value size = 2MB
>> Riak version = 1.4.1
>> n_val = 2
>> client threads total = 105
>> backend = bitcask
>> ring_creation_size = 128
>> node count = 7
>> node OS = RHEL 6.2
>> server RAM = 128GB
>> RAID = RAID0 across 8 SAS drives
>> FS = ext4
>> FS options = /dev/mapper/vg0-lv0 / ext4 
>> rw,noatime,barrier=0,stripe=512,data=ordered 0 0
>> bitcask size on one server = 133GB
>> AAE = off
>> interface = protobuf
>> client library = riak java client
>> file-max = 65536
>> 
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>> 
>> 
>> 
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>> 
>> 
>> 
>> -- 
>> Best Regards.
>> Lu Jie
>> 
>> 
>> 
>> -- 
>> Best Regards.
>> Lu Jie
>> _______________________________________________
>> riak-users mailing list
>> [email protected]
>> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
> 

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