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From kiran <kiran.sarvabho...@gmail.com>
Subject Re: HBase - Performance issue
Date Sat, 06 Sep 2014 18:37:46 GMT
Also the hbase version is 0.94.1


On Sun, Sep 7, 2014 at 12:00 AM, kiran <kiran.sarvabhotla@gmail.com> wrote:

> Lars,
>
> We are facing a similar situation on the similar cluster configuration...
> We are having high I/O wait percentages on some machines in our cluster...
> We have short circuit reads enabled but still we are facing the similar
> problem.. the cpu wait goes upto 50% also in some case while issuing scan
> commands with multiple threads.. Is there a work around other than applying
> the patch for 0.94.4 ??
>
> Thanks
> Kiran
>
>
> On Thu, Apr 25, 2013 at 12:12 AM, lars hofhansl <larsh@apache.org> wrote:
>
>> You may have run into https://issues.apache.org/jira/browse/HBASE-7336
>> (which is in 0.94.4)
>> (Although I had not observed this effect as much when short circuit reads
>> are enabled)
>>
>>
>>
>> ----- Original Message -----
>> From: kzurek <kzurek@proximetry.pl>
>> To: user@hbase.apache.org
>> Cc:
>> Sent: Wednesday, April 24, 2013 3:12 AM
>> Subject: HBase - Performance issue
>>
>> The problem is that when I'm putting my data (multithreaded client,
>> ~30MB/s
>> traffic outgoing) into the cluster the load is equally spread over all
>> RegionServer with 3.5% average CPU wait time (average CPU user: 51%). When
>> I've added similar, mutlithreaded client that Scans for, let say, 100 last
>> samples of randomly generated key from chosen time range, I'm getting high
>> CPU wait time (20% and up) on two (or more if there is higher number of
>> threads, default 10) random RegionServers. Therefore, machines that held
>> those RS are getting very hot - one of the consequences is that number of
>> store file is constantly increasing, up to the maximum limit. Rest of the
>> RS
>> are having 10-12% CPU wait time and everything seems to be OK (number of
>> store files varies so they are being compacted and not increasing over
>> time). Any ideas? Maybe  I could prioritize writes over reads somehow? Is
>> it
>> possible? If so what would be the best way to that and where it should be
>> placed - on the client or cluster side)?
>>
>> Cluster specification:
>> HBase Version    0.94.2-cdh4.2.0
>> Hadoop Version    2.0.0-cdh4.2.0
>> There are 6xDataNodes (5xHDD for storing data), 1xMasterNodes
>> Other settings:
>> - Bloom filters (ROWCOL) set
>> - Short circuit turned on
>> - HDFS Block Size: 128MB
>> - Java Heap Size of Namenode/Secondary Namenode in Bytes: 8 GiB
>> - Java Heap Size of HBase RegionServer in Bytes: 12 GiB
>> - Java Heap Size of HBase Master in Bytes: 4 GiB
>> - Java Heap Size of DataNode in Bytes: 1 GiB (default)
>> Number of regions per RegionServer: 19 (total 114 regions on 6 RS)
>> Key design: <UUID><TIMESTAMP> -> UUID: 1-10M, TIMESTAMP: 1-N
>> Table design: 1 column family with 20 columns of 8 bytes
>>
>> Get client:
>> Multiple threads
>> Each thread have its own tables instance with their Scanner.
>> Each thread have its own range of UUIDs and randomly draws beginning of
>> time
>> range to build rowkey properly (see above).
>> Each time Scan requests same amount of rows, but with random rowkey.
>>
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://apache-hbase.679495.n3.nabble.com/HBase-Performance-issue-tp4042836.html
>> Sent from the HBase User mailing list archive at Nabble.com.
>>
>>
>
>
> --
> Thank you
> Kiran Sarvabhotla
>
> -----Even a correct decision is wrong when it is taken late
>
>


-- 
Thank you
Kiran Sarvabhotla

-----Even a correct decision is wrong when it is taken late

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