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 >> >> > >> >> > 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) >> >> > >> > >>>> >> >> > >> > >> >> >> > >> > >> >> >> > >> > >> >> > >> > >> >> > >> >> >> > >> >> >> > >
