Root partition: OS and core program files

Swap: Size 2X system memory

Hadoop Slave node partitions: Hadoop should have its own partitions for Hadoop files and logs. Drives should be partitioned using ext3, ext4, or XFS, in that order of preference. HDFS on ext3 has been publicly tested on the Yahoo cluster, which makes it the safest choice for the underlying file system. The ext4 file system may have potential data loss issues with default options because of the "delayed writes" feature. XFS reportedly also has some data loss issues upon power failure. Do not use LVM; it adds latency and causes a bottleneck.  

On slave nodes only, all Hadoop partitions should be mounted individually from drives as "/grid/[0-n]".

Hadoop Slave Node Partitioning Configuration Example:

Master nodes -- Configured for reliability (RAID 10, dual Ethernet cards, dual power supplies, etc.)

Slave nodes -- RAID is not necessary, as failure on these nodes is managed automatically by the cluster. All data is stored across at least three different hosts, and therefore redundancy is built-in. Slave nodes should be built for speed and low cost.

Hortonworks Knowledge-Base article on options for selecting your underlying Linux file system: Best Practices: Linux File Systems for HDFS

CentOS partitioning documentation: Partitioning Your System

Reference architectures from other Hadoop clusters: Hadoop Reference Architectures