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HBase, mail # user - Storing images in Hbase


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Re: Storing images in Hbase
Varun Sharma 2013-01-22, 01:12
On Mon, Jan 21, 2013 at 5:10 PM, Varun Sharma <[EMAIL PROTECTED]> wrote:

> Thanks for the useful information. I wonder why you use only 5G heap when
> you have an 8G machine ? Is there a reason to not use all of it (the
> DataNode typically takes a 1G of RAM)
>
>
> On Sun, Jan 20, 2013 at 11:49 AM, Jack Levin <[EMAIL PROTECTED]> wrote:
>
>> I forgot to mention that I also have this setup:
>>
>> <property>
>>   <name>hbase.hregion.memstore.flush.size</name>
>>   <value>33554432</value>
>>   <description>Flush more often. Default: 67108864</description>
>> </property>
>>
>> This parameter works on per region amount, so this means if any of my
>> 400 (currently) regions on a regionserver has 30MB+ in memstore, the
>> hbase will flush it to disk.
>>
>>
>> Here are some metrics from a regionserver:
>>
>> requests=2, regions=370, stores=370, storefiles=1390,
>> storefileIndexSize=304, memstoreSize=2233, compactionQueueSize=0,
>> flushQueueSize=0, usedHeap=3516, maxHeap=4987,
>> blockCacheSize=790656256, blockCacheFree=255245888,
>> blockCacheCount=2436, blockCacheHitCount=218015828,
>> blockCacheMissCount=13514652, blockCacheEvictedCount=2561516,
>> blockCacheHitRatio=94, blockCacheHitCachingRatio=98
>>
>> Note, that memstore is only 2G, this particular regionserver HEAP is set
>> to 5G.
>>
>> And last but not least, its very important to have good GC setup:
>>
>> export HBASE_OPTS="$HBASE_OPTS -verbose:gc -Xms5000m
>> -XX:CMSInitiatingOccupancyFraction=70 -XX:+PrintGCDetails
>> -XX:+PrintGCDateStamps
>> -XX:+HeapDumpOnOutOfMemoryError -Xloggc:$HBASE_HOME/logs/gc-hbase.log \
>> -XX:MaxTenuringThreshold=15 -XX:SurvivorRatio=8 \
>> -XX:+UseParNewGC \
>> -XX:NewSize=128m -XX:MaxNewSize=128m \
>> -XX:-UseAdaptiveSizePolicy \
>> -XX:+CMSParallelRemarkEnabled \
>> -XX:-TraceClassUnloading
>> "
>>
>> -Jack
>>
>> On Thu, Jan 17, 2013 at 3:29 PM, Varun Sharma <[EMAIL PROTECTED]>
>> wrote:
>> > Hey Jack,
>> >
>> > Thanks for the useful information. By flush size being 15 %, do you mean
>> > the memstore flush size ? 15 % would mean close to 1G, have you seen any
>> > issues with flushes taking too long ?
>> >
>> > Thanks
>> > Varun
>> >
>> > On Sun, Jan 13, 2013 at 8:17 AM, Jack Levin <[EMAIL PROTECTED]> wrote:
>> >
>> >> That's right, Memstore size , not flush size is increased.  Filesize is
>> >> 10G. Overall write cache is 60% of heap and read cache is 20%.  Flush
>> size
>> >> is 15%.  64 maxlogs at 128MB. One namenode server, one secondary that
>> can
>> >> be promoted.  On the way to hbase images are written to a queue, so
>> that we
>> >> can take Hbase down for maintenance and still do inserts later.
>>  ImageShack
>> >> has ‘perma cache’ servers that allows writes and serving of data even
>> when
>> >> hbase is down for hours, consider it 4th replica 😉 outside of hadoop
>> >>
>> >> Jack
>> >>
>> >>  *From:* Mohit Anchlia <[EMAIL PROTECTED]>
>> >> *Sent:* ‎January‎ ‎13‎, ‎2013 ‎7‎:‎48‎ ‎AM
>> >> *To:* [EMAIL PROTECTED]
>> >> *Subject:* Re: Storing images in Hbase
>> >>
>> >> Thanks Jack for sharing this information. This definitely makes sense
>> when
>> >> using the type of caching layer. You mentioned about increasing write
>> >> cache, I am assuming you had to increase the following parameters in
>> >> addition to increase the memstore size:
>> >>
>> >> hbase.hregion.max.filesize
>> >> hbase.hregion.memstore.flush.size
>> >>
>> >> On Fri, Jan 11, 2013 at 9:47 AM, Jack Levin <[EMAIL PROTECTED]> wrote:
>> >>
>> >> > We buffer all accesses to HBASE with Varnish SSD based caching layer.
>> >> > So the impact for reads is negligible.  We have 70 node cluster, 8 GB
>> >> > of RAM per node, relatively weak nodes (intel core 2 duo), with
>> >> > 10-12TB per server of disks.  Inserting 600,000 images per day.  We
>> >> > have relatively little of compaction activity as we made our write
>> >> > cache much larger than read cache - so we don't experience region
>> file
>> >> > fragmentation as much.
>> >> >
>> >> > -Jack
>> >>