Disk Partitions Layout on Oracle Big Data Appliance Servers

Asset ID:	1-71-1625679.1
Update Date:	2016-08-03
Keywords:

Solution Type Technical Instruction Sure

Solution 1625679.1 : Disk Partitions Layout on Oracle Big Data Appliance Servers

Applies to:

Big Data Appliance X4-2 Full Rack - Version All Versions and later
Big Data Appliance X3-2 Hardware - Version All Versions and later
Big Data Appliance X4-2 Hardware - Version All Versions and later
Big Data Appliance X4-2 Starter Rack - Version All Versions and later
Big Data Appliance X3-2 Full Rack - Version All Versions and later
Linux x86-64

Goal

Describe the disk/partitions layout on Oracle Big Data Appliance (BDA) servers.

Solution

All BDA servers have identical hardware and they all provide both compute and storage.

The disk/partitions layout on all BDA servers is identical. From the the Oracle Big Data Appliance Software User's Guide Release 2 (2.4) section on "Logical Disk Layout", each server has 12 disks and the critical operating system is stored on disks 1 and 2.

The Logical Disk Layout looks like:

Disk

Description

1 to 2

150 gigabytes (GB) physical and logical partition, mirrored to create two copies, with the Linux operating system, all installed software, NameNode data, and MySQL Database data. The NameNode and MySQL Database data are replicated on two servers for a total of four copies.

2.8 terabytes (TB) HDFS data partition

3 to 12

Single HDFS or Oracle NoSQL Database data partition

On the BDA no hardware RAID is used but the / and /boot partitions are mirrored across the first 2 disks using mdadm (software RAID). All data partitions do not use RAID - this is referred to as a JBOD (just a bunch of disks) configuration and is recommended for Hadoop/HDFS.

The disk layout for a BDA single server is below:

OS Layout across 12 BDA Disks

disk-layout2

For the mirrored partitions (software RAID) managed by mdadm see /etc/mdadm.conf conf file and see /proc/mdstat for the current status.

For example output looks like:

1. /etc/mdadm.conf

# more /etc/mdadm.conf

# mdadm.conf written out by anaconda
DEVICE partitions
MAILADDR root
ARRAY /dev/md2 level=raid1 num-devices=2 uuid=6fcf70b1:93d86525:aaf33a34:88779cd
2
ARRAY /dev/md0 level=raid1 num-devices=2 uuid=8b8d9c33:8619721d:0a6de02e:11c3c53
0

2. /proc/mdstat

# more /proc/mdstat

Personalities : [raid1]
md0 : active raid1 sda1[0] sdb1[1]
      204736 blocks [2/2] [UU]

md2 : active raid1 sda2[0] sdb2[1]
      174079936 blocks [2/2] [UU]

unused devices: <none>

Attachments

This solution has no attachment