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 > >> > > >> > On Fri, Jan 11, 2013 at 9:40 AM, Mohit Anchlia < > [email protected]> > >> > wrote: > >> > > I think it really depends on volume of the traffic, data > distribution > >> per > >> > > region, how and when files compaction occurs, number of nodes in the > >> > > cluster. In my experience when it comes to blob data where you are > >> > serving > >> > > 10s of thousand+ requests/sec writes and reads then it's very > difficult > >> > to > >> > > manage HBase without very hard operations and maintenance in play. > Jack > >> > > earlier mentioned they have 1 billion images, It would be > interesting > >> to > >> > > know what they see in terms of compaction, no of requests per sec. > I'd > >> be > >> > > surprised that in high volume site it can be done without any > Caching > >> > layer > >> > > on the top to alleviate IO spikes that occurs because of GC and > >> > compactions. > >> > > > >> > > On Fri, Jan 11, 2013 at 7:27 AM, Mohammad Tariq <[email protected] > > > >> > wrote: > >> > > > >> > >> IMHO, if the image files are not too huge, Hbase can efficiently > serve > >> > the > >> > >> purpose. You can store some additional info along with the file > >> > depending > >> > >> upon your search criteria to make the search faster. Say if you > want > >> to > >> > >> fetch images by the type, you can store images in one column and > its > >> > >> extension in another column(jpg, tiff etc). > >> > >> > >> > >> BTW, what exactly is the problem which you are facing. You have > >> written > >> > >> "But I still cant do it"? > >> > >> > >> > >> Warm Regards, > >> > >> Tariq > >> > >> https://mtariq.jux.com/ > >> > >> > >> > >> > >> > >> On Fri, Jan 11, 2013 at 8:30 PM, Michael Segel < > >> > [email protected] > >> > >> >wrote: > >> > >> > >> > >> > That's a viable option. > >> > >> > HDFS reads are faster than HBase, but it would require first > hitting > >> > the > >> > >> > index in HBase which points to the file and then fetching the > file. > >> > >> > It could be faster... we found storing binary data in a sequence > >> file > >> > and > >> > >> > indexed on HBase to be faster than HBase, however, YMMV and HBase > >> has > >> > >> been > >> > >> > improved since we did that project.... > >> > >> > > >> > >> > > >> > >> > On Jan 10, 2013, at 10:56 PM, shashwat shriparv < > >> > >> [email protected]> > >> > >> > wrote: > >> > >> > > >> > >> > > Hi Kavish, > >> > >> > > > >> > >> > > i have a better idea for you copy your image files to a single > >> file > >> > on > >> > >> > > hdfs, and if new image comes append it to the existing image, > and > >> > keep > >> > >> > and > >> > >> > > update the metadata and the offset to the HBase. Because if you > >> put > >> > >> > bigger > >> > >> > > image in hbase it wil lead to some issue. > >> > >> > > > >> > >> > > > >> > >> > > > >> > >> > > ∞ > >> > >> > > Shashwat Shriparv > >> > >> > > > >> > >> > > > >> > >> > > > >> > >> > > On Fri, Jan 11, 2013 at 9:21 AM, lars hofhansl < > [email protected]> > >> > >> wrote: > >> > >> > > > >> > >> > >> Interesting. That's close to a PB if my math is correct. > >> > >> > >> Is there a write up about this somewhere? Something that we > could > >> > link > >> > >> > >> from the HBase homepage? > >> > >> > >> > >> > >> > >> -- Lars > >> > >> > >> > >> > >> > >> > >> > >> > >> ----- Original Message ----- > >> > >> > >> From: Jack Levin <[email protected]> > >> > >> > >> To: [email protected] > >> > >> > >> Cc: Andrew Purtell <[email protected]> > >> > >> > >> Sent: Thursday, January 10, 2013 9:24 AM > >> > >> > >> Subject: Re: Storing images in Hbase > >> > >> > >> > >> > >> > >> We stored about 1 billion images into hbase with file size up > to > >> > 10MB. > >> > >> > >> Its been running for close to 2 years without issues and > serves > >> > >> > >> delivery of images for Yfrog and ImageShack. If you have any > >> > >> > >> questions about the setup, I would be glad to answer them. > >> > >> > >> > >> > >> > >> -Jack > >> > >> > >> > >> > >> > >> On Sun, Jan 6, 2013 at 1:09 PM, Mohit Anchlia < > >> > [email protected] > >> > >> > > >> > >> > >> wrote: > >> > >> > >>> I have done extensive testing and have found that blobs don't > >> > belong > >> > >> in > >> > >> > >> the > >> > >> > >>> databases but are rather best left out on the file system. > >> Andrew > >> > >> > >> outlined > >> > >> > >>> issues that you'll face and not to mention IO issues when > >> > compaction > >> > >> > >> occurs > >> > >> > >>> over large files. > >> > >> > >>> > >> > >> > >>> On Sun, Jan 6, 2013 at 12:52 PM, Andrew Purtell < > >> > [email protected] > >> > >> > > >> > >> > >> wrote: > >> > >> > >>> > >> > >> > >>>> I meant this to say "a few really large values" > >> > >> > >>>> > >> > >> > >>>> On Sun, Jan 6, 2013 at 12:49 PM, Andrew Purtell < > >> > >> [email protected]> > >> > >> > >>>> wrote: > >> > >> > >>>> > >> > >> > >>>>> Consider if the split threshold is 2 GB but your one row > >> > contains > >> > >> 10 > >> > >> > >> GB > >> > >> > >>>> as > >> > >> > >>>>> really large value. > >> > >> > >>>> > >> > >> > >>>> > >> > >> > >>>> > >> > >> > >>>> > >> > >> > >>>> -- > >> > >> > >>>> Best regards, > >> > >> > >>>> > >> > >> > >>>> - Andy > >> > >> > >>>> > >> > >> > >>>> Problems worthy of attack prove their worth by hitting > back. - > >> > Piet > >> > >> > Hein > >> > >> > >>>> (via Tom White) > >> > >> > >>>> > >> > >> > >> > >> > >> > >> > >> > >> > > >> > >> > > >> > >> > >> > > >> >
