Hello,   A good place to start is usually (4 x fsimage_size) + 3GB Try about 15GB and see if that stabilizes Reports Manager.   Regards,   Ben ... View more

For the viewers of the post :   Few of the potential reasons which were figured out as the reasons for canary monitor failures :   1. Manual restarts of RegionServers. 2. Fetch fail by canary services in case of a remote read(usually related to network hitches). 3. Could also arise due to Hbase-Bug affecting the lower CDH releases (CHD 5.1 or below).   These are few of the items that we figured, please feel free to add more causative scenarios.   Thanks & Regards Pravdeep ... View more

Yes, the block count alert serves to indicate an early warning to a growing number of small files issue. While your DN can handle a lot of blocks in general, going too high will cause perf. issues. Small files will also cause a lot of processing overheads and slow down workloads generally. If you use CM Enterprise, you can use the Reports feature to find small files and who/where its top culprits are: http://www.cloudera.com/documentation/enterprise/latest/topics/cm_dg_disk_usage_reports.html Otherwise, a script to analyse a single hadoop fs -ls -R / output may also suffice. ... View more