Hi Niels and Bertrand, Thank you for you great advices. In our scenario, we need to store a steady stream of binary data into a circular storage,throughput and concurrency are the most important indicators.The first way seems work, but as hdfs is not friendly for small files, this approche may be not smooth enough.HBase is good, but not appropriate for us, both for throughput and storage.mongodb is quite good for web applications, but not suitable the scenario we meet all the same. we need a distributed storage system,with Highe throughput, HA,LB and secure. Maybe It act much like hbase, manager a lot of small file(hfile) as a large region. we manager a lot of small file as a large one. Perhaps we should develop it by ourselives.
Thank you. Lin Wukang 2013/7/25 Niels Basjes <ni...@basjes.nl> > A circular file on hdfs is not possible. > > Some of the ways around this limitation: > - Create a series of files and delete the oldest file when you have too > much. > - Put the data into an hbase table and do something similar. > - Use completely different technology like mongodb which has built in > support for a circular buffer (capped collection). > > Niels > > Hi all, > Is there any way to use a hdfs file as a Circular buffer? I mean, if I set > a quotas to a directory on hdfs, and writting data to a file in that > directory continuously. Once the quotas exceeded, I can redirect the writter > and write the data from the beginning of the file automatically . > >