Re: realtime hadoop
Daniel wrote: Also HDFS might be critical since to access your data you need to close the file Not anymore. Since 0.16 files are readable while being written to. Does this mean i can open some file as map input and the reduce output ? So i can update the files instead of creating new ones. No files are still write-once in hdfs, you cannot modify a file after it is closed. But if it is not closed you can still write more data into it, and other clients will be able to read this new data. Also if i want to do query in the records, should i rather use Hbase instead of HDFS? - say if we have large size of data stored as (key, value). HDFS has file system api, there is no notion of a record in it, just files and bytes. Depending on how you define a record you can use different systems including HBase and Pig. These two work well for table-like data collections. Or you can write your own MapReduce job to do processing of a big key-value dataset. Regards, --Konstantin Thanks. it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. It looks like you do not need very strict guarantees. I think you can use hdfs as a data-storage. Don't know what kind of data-processing you do, but I agree with Stefan that map-reduce is designed for batch tasks rather than for real-time processing. Stefan Groschupf wrote: Hadoop might be the wrong technology for you. Map Reduce is a batch processing mechanism. Also HDFS might be critical since to access your data you need to close the file - means you might have many small file, a situation where hdfs is not very strong (namespace is hold in memory). Hbase might be an interesting tool for you, also zookeeper if you want to do something home grown... On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim ~~~ 101tec Inc. Menlo Park, California, USA http://www.101tec.com
Re: realtime hadoop
2008/6/24 Konstantin Shvachko <[EMAIL PROTECTED]>: > > Also HDFS might be critical since to access your data you need to close > the file > > Not anymore. Since 0.16 files are readable while being written to. Does this mean i can open some file as map input and the reduce output ? So i can update the files instead of creating new ones. Also if i want to do query in the records, should i rather use Hbase instead of HDFS? - say if we have large size of data stored as (key, value). Thanks. > > > >> it as fast as possible. I need to be able to maintain some guaranteed > >> max. processing time, for example under 3 minutes. > > It looks like you do not need very strict guarantees. > I think you can use hdfs as a data-storage. > Don't know what kind of data-processing you do, but I agree with Stefan > that map-reduce is designed for batch tasks rather than for real-time > processing. > > > > > Stefan Groschupf wrote: > >> Hadoop might be the wrong technology for you. >> Map Reduce is a batch processing mechanism. Also HDFS might be critical >> since to access your data you need to close the file - means you might have >> many small file, a situation where hdfs is not very strong (namespace is >> hold in memory). >> Hbase might be an interesting tool for you, also zookeeper if you want to >> do something home grown... >> >> >> >> On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: >> >> Hi! >>> >>> I am considering using Hadoop for (almost) realime data processing. I >>> have data coming every second and I would like to use hadoop cluster >>> to process >>> it as fast as possible. I need to be able to maintain some guaranteed >>> max. processing time, for example under 3 minutes. >>> >>> Does anybody have experience with using Hadoop in such manner? I will >>> appreciate if you can share your experience or give me pointers >>> to some articles or pages on the subject. >>> >>> Vadim >>> >>> >> ~~~ >> 101tec Inc. >> Menlo Park, California, USA >> http://www.101tec.com >> >> >> >>
Re: realtime hadoop
We wrote some custom tools that poll for new data and launch jobs periodically. Matt On Tue, 2008-06-24 at 09:27 -0700, Vadim Zaliva wrote: > Matt, > > How do you manage your tasks? Do you lauch them periodically or keep > them somehow running and feed them data? > > Vadim > > > On Mon, Jun 23, 2008 at 21:54, Matt Kent <[EMAIL PROTECTED]> wrote: > > We use Hadoop in a similar manner, to process batches of data in > > real-time every few minutes. However, we do substantial amounts of > > processing on that data, so we use Hadoop to distribute our computation. > > Unless you have a significant amount of work to be done, I wouldn't > > recommend using Hadoop because it's not worth the overhead of launching > > the jobs and moving the data around. > > > > Matt > > > > On Tue, 2008-06-24 at 13:34 +1000, Ian Holsman (Lists) wrote: > >> Interesting. > >> we are planning on using hadoop to provide 'near' real time log > >> analysis. we plan on having files close every 5 minutes (1 per log > >> machine, so 80 files every 5 minutes) and then have a m/r to merge it > >> into a single file that will get processed by other jobs later on. > >> > >> do you think this will namespace will explode? > >> > >> I wasn't thinking of clouddb.. it might be an interesting alternative > >> once it is a bit more stable. > >> > >> regards > >> Ian > >> > >> Stefan Groschupf wrote: > >> > Hadoop might be the wrong technology for you. > >> > Map Reduce is a batch processing mechanism. Also HDFS might be critical > >> > since to access your data you need to close the file - means you might > >> > have many small file, a situation where hdfs is not very strong > >> > (namespace is hold in memory). > >> > Hbase might be an interesting tool for you, also zookeeper if you want > >> > to do something home grown... > >> > > >> > > >> > > >> > On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: > >> > > >> >> Hi! > >> >> > >> >> I am considering using Hadoop for (almost) realime data processing. I > >> >> have data coming every second and I would like to use hadoop cluster > >> >> to process > >> >> it as fast as possible. I need to be able to maintain some guaranteed > >> >> max. processing time, for example under 3 minutes. > >> >> > >> >> Does anybody have experience with using Hadoop in such manner? I will > >> >> appreciate if you can share your experience or give me pointers > >> >> to some articles or pages on the subject. > >> >> > >> >> Vadim > >> >> > >> > > >> > ~~~ > >> > 101tec Inc. > >> > Menlo Park, California, USA > >> > http://www.101tec.com > >> > > >> > > >> > > > >
Re: realtime hadoop
On Jun 23, 2008, at 9:54 PM, Matt Kent wrote: Unless you have a significant amount of work to be done, I wouldn't recommend using Hadoop because it's not worth the overhead of launching the jobs and moving the data around. I think part of the tradeoff is having a system that is resilient to failure against work that must get done, regardless of the amount of work. ckw -- Chris K Wensel [EMAIL PROTECTED] http://chris.wensel.net/ http://www.cascading.org/
Re: realtime hadoop
Matt, How do you manage your tasks? Do you lauch them periodically or keep them somehow running and feed them data? Vadim On Mon, Jun 23, 2008 at 21:54, Matt Kent <[EMAIL PROTECTED]> wrote: > We use Hadoop in a similar manner, to process batches of data in > real-time every few minutes. However, we do substantial amounts of > processing on that data, so we use Hadoop to distribute our computation. > Unless you have a significant amount of work to be done, I wouldn't > recommend using Hadoop because it's not worth the overhead of launching > the jobs and moving the data around. > > Matt > > On Tue, 2008-06-24 at 13:34 +1000, Ian Holsman (Lists) wrote: >> Interesting. >> we are planning on using hadoop to provide 'near' real time log >> analysis. we plan on having files close every 5 minutes (1 per log >> machine, so 80 files every 5 minutes) and then have a m/r to merge it >> into a single file that will get processed by other jobs later on. >> >> do you think this will namespace will explode? >> >> I wasn't thinking of clouddb.. it might be an interesting alternative >> once it is a bit more stable. >> >> regards >> Ian >> >> Stefan Groschupf wrote: >> > Hadoop might be the wrong technology for you. >> > Map Reduce is a batch processing mechanism. Also HDFS might be critical >> > since to access your data you need to close the file - means you might >> > have many small file, a situation where hdfs is not very strong >> > (namespace is hold in memory). >> > Hbase might be an interesting tool for you, also zookeeper if you want >> > to do something home grown... >> > >> > >> > >> > On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: >> > >> >> Hi! >> >> >> >> I am considering using Hadoop for (almost) realime data processing. I >> >> have data coming every second and I would like to use hadoop cluster >> >> to process >> >> it as fast as possible. I need to be able to maintain some guaranteed >> >> max. processing time, for example under 3 minutes. >> >> >> >> Does anybody have experience with using Hadoop in such manner? I will >> >> appreciate if you can share your experience or give me pointers >> >> to some articles or pages on the subject. >> >> >> >> Vadim >> >> >> > >> > ~~~ >> > 101tec Inc. >> > Menlo Park, California, USA >> > http://www.101tec.com >> > >> > >> > >
Re: realtime hadoop
Fernando Padilla wrote: One use case I have a question about, is using Hadoop to power a web search or other query. So the full job should be done in under a second, from start to finish. I don't think you should be using hadoop to answer the results of a user's search query. you should be looking at things like SOLR (with the distributed patch), or CloudDB/Mysql Clusters. some good research has also been done on this.. see CRUSH by Sage Weil :- www.ssrc.ucsc.edu/Papers/weil-sc06.pdf or the work on Chord# for wikipedia called 'onscale' :- http://onscale.de/onscaledb.html both would be better suited for OLTP type operations I would think. You know, you have a huge datastore, and you have to run a query against that, implemented as a MR query. Is there a way to optimize that use case, where the code doesn't change, but maybe the input parameters of the job? So a MR job could reuse the java code, and even the same JVM to avoid all of the startup costs.. I bet hadoop isn't built for that yet (and enough reasons not to support it yet).. but maybe it's a usecase that shouldn't be totally ignored. And if you think about it, this is similar to what HBase is doing, at least the query execution part.. A dedicated MR daemon running ontop of the Hadoop infrastructure, so you don't incur the cost of distributing and starting fresh MR/JVM processes across the cluster.. maybe someone would want to refactor this thought process a little bit.. Matt Kent wrote: We use Hadoop in a similar manner, to process batches of data in real-time every few minutes. However, we do substantial amounts of processing on that data, so we use Hadoop to distribute our computation. Unless you have a significant amount of work to be done, I wouldn't recommend using Hadoop because it's not worth the overhead of launching the jobs and moving the data around. Matt On Tue, 2008-06-24 at 13:34 +1000, Ian Holsman (Lists) wrote: Interesting. we are planning on using hadoop to provide 'near' real time log analysis. we plan on having files close every 5 minutes (1 per log machine, so 80 files every 5 minutes) and then have a m/r to merge it into a single file that will get processed by other jobs later on. do you think this will namespace will explode? I wasn't thinking of clouddb.. it might be an interesting alternative once it is a bit more stable. regards Ian Stefan Groschupf wrote: Hadoop might be the wrong technology for you. Map Reduce is a batch processing mechanism. Also HDFS might be critical since to access your data you need to close the file - means you might have many small file, a situation where hdfs is not very strong (namespace is hold in memory). Hbase might be an interesting tool for you, also zookeeper if you want to do something home grown... On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim ~~~ 101tec Inc. Menlo Park, California, USA http://www.101tec.com
Re: realtime hadoop
Matt Kent wrote: We use Hadoop in a similar manner, to process batches of data in real-time every few minutes. However, we do substantial amounts of processing on that data, so we use Hadoop to distribute our computation. Unless you have a significant amount of work to be done, I wouldn't recommend using Hadoop because it's not worth the overhead of launching the jobs and moving the data around. Thanks Matt. we are boiling the ocean with the data so to speak.. so thats cool. we are also looking at supplementing the m/r jobs with data coming in from spread to get the 'instant' analysis parts of our feedback systems. Regards Ian Matt On Tue, 2008-06-24 at 13:34 +1000, Ian Holsman (Lists) wrote: Interesting. we are planning on using hadoop to provide 'near' real time log analysis. we plan on having files close every 5 minutes (1 per log machine, so 80 files every 5 minutes) and then have a m/r to merge it into a single file that will get processed by other jobs later on. do you think this will namespace will explode? I wasn't thinking of clouddb.. it might be an interesting alternative once it is a bit more stable. regards Ian Stefan Groschupf wrote: Hadoop might be the wrong technology for you. Map Reduce is a batch processing mechanism. Also HDFS might be critical since to access your data you need to close the file - means you might have many small file, a situation where hdfs is not very strong (namespace is hold in memory). Hbase might be an interesting tool for you, also zookeeper if you want to do something home grown... On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim ~~~ 101tec Inc. Menlo Park, California, USA http://www.101tec.com
Re: realtime hadoop
One use case I have a question about, is using Hadoop to power a web search or other query. So the full job should be done in under a second, from start to finish. You know, you have a huge datastore, and you have to run a query against that, implemented as a MR query. Is there a way to optimize that use case, where the code doesn't change, but maybe the input parameters of the job? So a MR job could reuse the java code, and even the same JVM to avoid all of the startup costs.. I bet hadoop isn't built for that yet (and enough reasons not to support it yet).. but maybe it's a usecase that shouldn't be totally ignored. And if you think about it, this is similar to what HBase is doing, at least the query execution part.. A dedicated MR daemon running ontop of the Hadoop infrastructure, so you don't incur the cost of distributing and starting fresh MR/JVM processes across the cluster.. maybe someone would want to refactor this thought process a little bit.. Matt Kent wrote: We use Hadoop in a similar manner, to process batches of data in real-time every few minutes. However, we do substantial amounts of processing on that data, so we use Hadoop to distribute our computation. Unless you have a significant amount of work to be done, I wouldn't recommend using Hadoop because it's not worth the overhead of launching the jobs and moving the data around. Matt On Tue, 2008-06-24 at 13:34 +1000, Ian Holsman (Lists) wrote: Interesting. we are planning on using hadoop to provide 'near' real time log analysis. we plan on having files close every 5 minutes (1 per log machine, so 80 files every 5 minutes) and then have a m/r to merge it into a single file that will get processed by other jobs later on. do you think this will namespace will explode? I wasn't thinking of clouddb.. it might be an interesting alternative once it is a bit more stable. regards Ian Stefan Groschupf wrote: Hadoop might be the wrong technology for you. Map Reduce is a batch processing mechanism. Also HDFS might be critical since to access your data you need to close the file - means you might have many small file, a situation where hdfs is not very strong (namespace is hold in memory). Hbase might be an interesting tool for you, also zookeeper if you want to do something home grown... On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim ~~~ 101tec Inc. Menlo Park, California, USA http://www.101tec.com
Re: realtime hadoop
We use Hadoop in a similar manner, to process batches of data in real-time every few minutes. However, we do substantial amounts of processing on that data, so we use Hadoop to distribute our computation. Unless you have a significant amount of work to be done, I wouldn't recommend using Hadoop because it's not worth the overhead of launching the jobs and moving the data around. Matt On Tue, 2008-06-24 at 13:34 +1000, Ian Holsman (Lists) wrote: > Interesting. > we are planning on using hadoop to provide 'near' real time log > analysis. we plan on having files close every 5 minutes (1 per log > machine, so 80 files every 5 minutes) and then have a m/r to merge it > into a single file that will get processed by other jobs later on. > > do you think this will namespace will explode? > > I wasn't thinking of clouddb.. it might be an interesting alternative > once it is a bit more stable. > > regards > Ian > > Stefan Groschupf wrote: > > Hadoop might be the wrong technology for you. > > Map Reduce is a batch processing mechanism. Also HDFS might be critical > > since to access your data you need to close the file - means you might > > have many small file, a situation where hdfs is not very strong > > (namespace is hold in memory). > > Hbase might be an interesting tool for you, also zookeeper if you want > > to do something home grown... > > > > > > > > On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: > > > >> Hi! > >> > >> I am considering using Hadoop for (almost) realime data processing. I > >> have data coming every second and I would like to use hadoop cluster > >> to process > >> it as fast as possible. I need to be able to maintain some guaranteed > >> max. processing time, for example under 3 minutes. > >> > >> Does anybody have experience with using Hadoop in such manner? I will > >> appreciate if you can share your experience or give me pointers > >> to some articles or pages on the subject. > >> > >> Vadim > >> > > > > ~~~ > > 101tec Inc. > > Menlo Park, California, USA > > http://www.101tec.com > > > > >
Re: realtime hadoop
Interesting. we are planning on using hadoop to provide 'near' real time log analysis. we plan on having files close every 5 minutes (1 per log machine, so 80 files every 5 minutes) and then have a m/r to merge it into a single file that will get processed by other jobs later on. do you think this will namespace will explode? I wasn't thinking of clouddb.. it might be an interesting alternative once it is a bit more stable. regards Ian Stefan Groschupf wrote: Hadoop might be the wrong technology for you. Map Reduce is a batch processing mechanism. Also HDFS might be critical since to access your data you need to close the file - means you might have many small file, a situation where hdfs is not very strong (namespace is hold in memory). Hbase might be an interesting tool for you, also zookeeper if you want to do something home grown... On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim ~~~ 101tec Inc. Menlo Park, California, USA http://www.101tec.com
Re: realtime hadoop
> Also HDFS might be critical since to access your data you need to close the file Not anymore. Since 0.16 files are readable while being written to. >> it as fast as possible. I need to be able to maintain some guaranteed >> max. processing time, for example under 3 minutes. It looks like you do not need very strict guarantees. I think you can use hdfs as a data-storage. Don't know what kind of data-processing you do, but I agree with Stefan that map-reduce is designed for batch tasks rather than for real-time processing. Stefan Groschupf wrote: Hadoop might be the wrong technology for you. Map Reduce is a batch processing mechanism. Also HDFS might be critical since to access your data you need to close the file - means you might have many small file, a situation where hdfs is not very strong (namespace is hold in memory). Hbase might be an interesting tool for you, also zookeeper if you want to do something home grown... On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim ~~~ 101tec Inc. Menlo Park, California, USA http://www.101tec.com
Re: realtime hadoop
Vadim, Depending on the nature of your data, CouchDB (http://couchdb.org) might be worth looking into. It speaks JSON natively, and has real-time map/reduce support. The 0.8.0 release is imminent (don't bother with 0.7.2), and the community is active. We're using it for something similar to what you describe, and it's working well. Chris -- Chris Anderson http://jchris.mfdz.com
Re: realtime hadoop
Hadoop might be the wrong technology for you. Map Reduce is a batch processing mechanism. Also HDFS might be critical since to access your data you need to close the file - means you might have many small file, a situation where hdfs is not very strong (namespace is hold in memory). Hbase might be an interesting tool for you, also zookeeper if you want to do something home grown... On Jun 23, 2008, at 11:31 PM, Vadim Zaliva wrote: Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim ~~~ 101tec Inc. Menlo Park, California, USA http://www.101tec.com
realtime hadoop
Hi! I am considering using Hadoop for (almost) realime data processing. I have data coming every second and I would like to use hadoop cluster to process it as fast as possible. I need to be able to maintain some guaranteed max. processing time, for example under 3 minutes. Does anybody have experience with using Hadoop in such manner? I will appreciate if you can share your experience or give me pointers to some articles or pages on the subject. Vadim
