The Apache HBase Medium Object Storage (MOB) feature was introduced by HBASE-11339. This feature improves low latency read and write access for moderately-sized values (ideally from 100K to 10MB based on our testing results), making it well-suited for storing documents, images, and other moderately-sized objects . The Apache HBase MOB feature achieves this improvement by separating IO paths for file references and MOB objects, applying different compaction policies to MOBs and thus reducing write amplification created by HBase’s compactions.
One of the most fundamental aspects a data model can convey is how something changes over time. This makes sense when considering that we build data models to capture what is happening in the real world, and the real world is constantly changing. The challenge is that it’s not just that new things are occurring, it’s that existing things are changing too, and if in our data models we overwrite the old state of an entity with the new state then we have lost information about the change.
Learn how to use Cloudera to spin up Apache Hadoop clusters across multiple cloud providers to take advantage of competing prices and avoid infrastructure lock-in.
Why is a multi-cloud strategy important?
In the early days of Cloudera, it was a fair assumption that our software would be running on industry-standard servers that were purchased, owned, and operated by the client in their own data center. In the last few years,
With modern businesses dealing with an ever-increasing volume of data, and an expanding set of data sources, the data engineering process that enables analysis, visualization, and reporting only becomes more important.
When considering running data engineering workloads in the public cloud, there are capabilities which enable different operational models from on-premises deployments. The key factors here are the presence of a distinct storage layer within the cloud environment, and the ability to provision compute resources on-demand (e.g.: with Amazon’s S3 and EC2 respectively).
System maintenance operations such as updating operating systems, and applying security patches or hotfixes are routine operations in any data center. DataNodes undergoing such maintenance operations can go offline for anywhere from a few minutes to several hours. By design, Apache Hadoop HDFS can handle DataNodes going down. However, any uncoordinated maintenance operations on several DataNodes at the same time could lead to temporary data availability issues. HDFS currently supports the following features for performing planned maintenance activity:
- Rolling Upgrade
- HDFS supports using Maintenance State (Starting with CDH 5.11)
The rolling upgrade process helps to upgrade the cluster software without taking the cluster offline.